diff --git a/l10n/en-US/viewer.properties b/l10n/en-US/viewer.properties
index dadfe4143..c52020c5c 100644
--- a/l10n/en-US/viewer.properties
+++ b/l10n/en-US/viewer.properties
@@ -146,6 +146,7 @@ loading_error_indicator=Error
 loading_error=An error occurred while loading the PDF.
 invalid_file_error=Invalid or corrupted PDF file.
 missing_file_error=Missing PDF file.
+unexpected_response_error=Unexpected server response.
 
 # LOCALIZATION NOTE (text_annotation_type.alt): This is used as a tooltip.
 # "{{type}}" will be replaced with an annotation type from a list defined in
diff --git a/src/core/worker.js b/src/core/worker.js
index 78a91d317..7dca8f05d 100644
--- a/src/core/worker.js
+++ b/src/core/worker.js
@@ -14,11 +14,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-/* globals error, globalScope, InvalidPDFException, info,
-           MissingPDFException, PasswordException, PDFJS, Promise,
-           UnknownErrorException, NetworkManager, LocalPdfManager,
-           NetworkPdfManager, XRefParseException, createPromiseCapability,
-           isInt, PasswordResponses, MessageHandler, Ref, RANGE_CHUNK_SIZE */
+/* globals PDFJS, createPromiseCapability, LocalPdfManager, NetworkPdfManager,
+           NetworkManager, isInt, RANGE_CHUNK_SIZE, MissingPDFException,
+           UnexpectedResponseException, PasswordException, Promise,
+           PasswordResponses, InvalidPDFException, UnknownErrorException,
+           XRefParseException, Ref, info, globalScope, error, MessageHandler */
 
 'use strict';
 
@@ -141,14 +141,16 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
         },
 
         onError: function onError(status) {
+          var exception;
           if (status === 404) {
-            var exception = new MissingPDFException('Missing PDF "' +
-                                                    source.url + '".');
-            handler.send('MissingPDF', { exception: exception });
+            exception = new MissingPDFException('Missing PDF "' +
+                                                source.url + '".');
+            handler.send('MissingPDF', exception);
           } else {
-            handler.send('DocError', 'Unexpected server response (' +
-                         status + ') while retrieving PDF "' +
-                         source.url + '".');
+            exception = new UnexpectedResponseException(
+              'Unexpected server response (' + status +
+              ') while retrieving PDF "' + source.url + '".', status);
+            handler.send('UnexpectedResponse', exception);
           }
         },
 
@@ -200,26 +202,19 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
       var onFailure = function(e) {
         if (e instanceof PasswordException) {
           if (e.code === PasswordResponses.NEED_PASSWORD) {
-            handler.send('NeedPassword', {
-              exception: e
-            });
+            handler.send('NeedPassword', e);
           } else if (e.code === PasswordResponses.INCORRECT_PASSWORD) {
-            handler.send('IncorrectPassword', {
-              exception: e
-            });
+            handler.send('IncorrectPassword', e);
           }
         } else if (e instanceof InvalidPDFException) {
-          handler.send('InvalidPDF', {
-            exception: e
-          });
+          handler.send('InvalidPDF', e);
         } else if (e instanceof MissingPDFException) {
-          handler.send('MissingPDF', {
-            exception: e
-          });
+          handler.send('MissingPDF', e);
+        } else if (e instanceof UnexpectedResponseException) {
+          handler.send('UnexpectedResponse', e);
         } else {
-          handler.send('UnknownError', {
-            exception: new UnknownErrorException(e.message, e.toString())
-          });
+          handler.send('UnknownError',
+                       new UnknownErrorException(e.message, e.toString()));
         }
       };
 
diff --git a/src/display/api.js b/src/display/api.js
index 9850c0dc8..a8840db98 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -14,11 +14,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-/* globals CanvasGraphics, combineUrl, createScratchCanvas, error,
-           FontLoader, globalScope, info, isArrayBuffer, loadJpegStream,
-           MessageHandler, PDFJS, Promise, StatTimer, warn,
-           PasswordResponses, Util, loadScript, createPromiseCapability,
-           FontFace */
+/* globals PDFJS, isArrayBuffer, error, combineUrl, createPromiseCapability,
+           StatTimer, globalScope, MessageHandler, info, FontLoader, Util, warn,
+           Promise, PasswordResponses, PasswordException, InvalidPDFException,
+           MissingPDFException, UnknownErrorException, FontFace, loadJpegStream,
+           createScratchCanvas, CanvasGraphics, UnexpectedResponseException */
 
 'use strict';
 
@@ -865,36 +865,46 @@ var WorkerTransport = (function WorkerTransportClosure() {
         this.workerReadyCapability.resolve(pdfDocument);
       }, this);
 
-      messageHandler.on('NeedPassword', function transportPassword(data) {
+      messageHandler.on('NeedPassword',
+                        function transportNeedPassword(exception) {
         if (this.passwordCallback) {
           return this.passwordCallback(updatePassword,
                                        PasswordResponses.NEED_PASSWORD);
         }
-        this.workerReadyCapability.reject(data.exception.message,
-                                          data.exception);
+        this.workerReadyCapability.reject(
+          new PasswordException(exception.message, exception.code));
       }, this);
 
-      messageHandler.on('IncorrectPassword', function transportBadPass(data) {
+      messageHandler.on('IncorrectPassword',
+                        function transportIncorrectPassword(exception) {
         if (this.passwordCallback) {
           return this.passwordCallback(updatePassword,
                                        PasswordResponses.INCORRECT_PASSWORD);
         }
-        this.workerReadyCapability.reject(data.exception.message,
-                                          data.exception);
+        this.workerReadyCapability.reject(
+          new PasswordException(exception.message, exception.code));
       }, this);
 
-      messageHandler.on('InvalidPDF', function transportInvalidPDF(data) {
-        this.workerReadyCapability.reject(data.exception.name, data.exception);
+      messageHandler.on('InvalidPDF', function transportInvalidPDF(exception) {
+        this.workerReadyCapability.reject(
+          new InvalidPDFException(exception.message));
       }, this);
 
-      messageHandler.on('MissingPDF', function transportMissingPDF(data) {
-        this.workerReadyCapability.reject(data.exception.message,
-                                          data.exception);
+      messageHandler.on('MissingPDF', function transportMissingPDF(exception) {
+        this.workerReadyCapability.reject(
+          new MissingPDFException(exception.message));
       }, this);
 
-      messageHandler.on('UnknownError', function transportUnknownError(data) {
-        this.workerReadyCapability.reject(data.exception.message,
-                                          data.exception);
+      messageHandler.on('UnexpectedResponse',
+                        function transportUnexpectedResponse(exception) {
+        this.workerReadyCapability.reject(
+          new UnexpectedResponseException(exception.message, exception.status));
+      }, this);
+
+      messageHandler.on('UnknownError',
+                        function transportUnknownError(exception) {
+        this.workerReadyCapability.reject(
+          new UnknownErrorException(exception.message, exception.details));
       }, this);
 
       messageHandler.on('DataLoaded', function transportPage(data) {
@@ -990,10 +1000,6 @@ var WorkerTransport = (function WorkerTransportClosure() {
         }
       }, this);
 
-      messageHandler.on('DocError', function transportDocError(data) {
-        this.workerReadyCapability.reject(data);
-      }, this);
-
       messageHandler.on('PageError', function transportError(data) {
         var page = this.pageCache[data.pageNum - 1];
         var intentState = page.intentStates[data.intent];
diff --git a/src/shared/util.js b/src/shared/util.js
index 201ca3e0f..7deb99175 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -342,6 +342,7 @@ var PasswordException = (function PasswordExceptionClosure() {
 
   return PasswordException;
 })();
+PDFJS.PasswordException = PasswordException;
 
 var UnknownErrorException = (function UnknownErrorExceptionClosure() {
   function UnknownErrorException(msg, details) {
@@ -355,6 +356,7 @@ var UnknownErrorException = (function UnknownErrorExceptionClosure() {
 
   return UnknownErrorException;
 })();
+PDFJS.UnknownErrorException = UnknownErrorException;
 
 var InvalidPDFException = (function InvalidPDFExceptionClosure() {
   function InvalidPDFException(msg) {
@@ -367,6 +369,7 @@ var InvalidPDFException = (function InvalidPDFExceptionClosure() {
 
   return InvalidPDFException;
 })();
+PDFJS.InvalidPDFException = InvalidPDFException;
 
 var MissingPDFException = (function MissingPDFExceptionClosure() {
   function MissingPDFException(msg) {
@@ -379,6 +382,22 @@ var MissingPDFException = (function MissingPDFExceptionClosure() {
 
   return MissingPDFException;
 })();
+PDFJS.MissingPDFException = MissingPDFException;
+
+var UnexpectedResponseException =
+    (function UnexpectedResponseExceptionClosure() {
+  function UnexpectedResponseException(msg, status) {
+    this.name = 'UnexpectedResponseException';
+    this.message = msg;
+    this.status = status;
+  }
+
+  UnexpectedResponseException.prototype = new Error();
+  UnexpectedResponseException.constructor = UnexpectedResponseException;
+
+  return UnexpectedResponseException;
+})();
+PDFJS.UnexpectedResponseException = UnexpectedResponseException;
 
 var NotImplementedException = (function NotImplementedExceptionClosure() {
   function NotImplementedException(msg) {
diff --git a/test/unit/api_spec.js b/test/unit/api_spec.js
index f82e960d9..c6bf6609e 100644
--- a/test/unit/api_spec.js
+++ b/test/unit/api_spec.js
@@ -1,14 +1,14 @@
 /* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
 /* globals PDFJS, expect, it, describe, Promise, combineUrl, waitsFor,
-           isArray */
+           isArray, MissingPDFException */
 
 'use strict';
 
 describe('api', function() {
   // TODO run with worker enabled
   var basicApiUrl = combineUrl(window.location.href, '../pdfs/basicapi.pdf');
-  function waitsForPromise(promise, successCallback) {
+  function waitsForPromiseResolved(promise, successCallback) {
     var data;
     promise.then(function(val) {
       data = val;
@@ -22,11 +22,25 @@ describe('api', function() {
       return data !== undefined;
     }, 20000);
   }
+  function waitsForPromiseRejected(promise, failureCallback) {
+    var data;
+    promise.then(function(val) {
+      // Shouldn't get here.
+      expect(false).toEqual(true);
+    },
+    function(error) {
+      data = error;
+      failureCallback(data);
+    });
+    waitsFor(function() {
+      return data !== undefined;
+    }, 20000);
+  }
   describe('PDFJS', function() {
     describe('getDocument', function() {
       it('creates pdf doc from URL', function() {
         var promise = PDFJS.getDocument(basicApiUrl);
-        waitsForPromise(promise, function(data) {
+        waitsForPromiseResolved(promise, function(data) {
           expect(true).toEqual(true);
         });
       });
@@ -61,16 +75,24 @@ describe('api', function() {
         expect(typedArrayPdf.length).toEqual(105779);
 
         var promise = PDFJS.getDocument(typedArrayPdf);
-        waitsForPromise(promise, function(data) {
+        waitsForPromiseResolved(promise, function(data) {
           expect(true).toEqual(true);
         });
       });
+      it('creates pdf doc from non-existent URL', function() {
+        var nonExistentUrl = combineUrl(window.location.href,
+                                        '../pdfs/non-existent.pdf');
+        var promise = PDFJS.getDocument(nonExistentUrl);
+        waitsForPromiseRejected(promise, function(error) {
+          expect(error instanceof MissingPDFException).toEqual(true);
+        });
+      });
     });
   });
   describe('PDFDocument', function() {
     var promise = PDFJS.getDocument(basicApiUrl);
     var doc;
-    waitsForPromise(promise, function(data) {
+    waitsForPromiseResolved(promise, function(data) {
       doc = data;
     });
     it('gets number of pages', function() {
@@ -81,7 +103,7 @@ describe('api', function() {
     });
     it('gets page', function() {
       var promise = doc.getPage(1);
-      waitsForPromise(promise, function(data) {
+      waitsForPromiseResolved(promise, function(data) {
         expect(true).toEqual(true);
       });
     });
@@ -89,32 +111,32 @@ describe('api', function() {
       // reference to second page
       var ref = {num: 17, gen: 0};
       var promise = doc.getPageIndex(ref);
-      waitsForPromise(promise, function(pageIndex) {
+      waitsForPromiseResolved(promise, function(pageIndex) {
         expect(pageIndex).toEqual(1);
       });
     });
     it('gets destinations', function() {
       var promise = doc.getDestinations();
-      waitsForPromise(promise, function(data) {
+      waitsForPromiseResolved(promise, function(data) {
         expect(data).toEqual({ chapter1: [{ gen: 0, num: 17 }, { name: 'XYZ' },
                                           0, 841.89, null] });
       });
     });
     it('gets attachments', function() {
       var promise = doc.getAttachments();
-      waitsForPromise(promise, function (data) {
+      waitsForPromiseResolved(promise, function (data) {
         expect(data).toEqual(null);
       });
     });
     it('gets javascript', function() {
       var promise = doc.getJavaScript();
-      waitsForPromise(promise, function (data) {
+      waitsForPromiseResolved(promise, function (data) {
         expect(data).toEqual([]);
       });
     });
     it('gets outline', function() {
       var promise = doc.getOutline();
-      waitsForPromise(promise, function(outline) {
+      waitsForPromiseResolved(promise, function(outline) {
         // Two top level entries.
         expect(outline.length).toEqual(2);
         // Make sure some basic attributes are set.
@@ -125,26 +147,26 @@ describe('api', function() {
     });
     it('gets metadata', function() {
       var promise = doc.getMetadata();
-      waitsForPromise(promise, function(metadata) {
+      waitsForPromiseResolved(promise, function(metadata) {
         expect(metadata.info['Title']).toEqual('Basic API Test');
         expect(metadata.metadata.get('dc:title')).toEqual('Basic API Test');
       });
     });
     it('gets data', function() {
       var promise = doc.getData();
-      waitsForPromise(promise, function (data) {
+      waitsForPromiseResolved(promise, function (data) {
         expect(true).toEqual(true);
       });
     });
     it('gets filesize in bytes', function() {
       var promise = doc.getDownloadInfo();
-      waitsForPromise(promise, function (data) {
+      waitsForPromiseResolved(promise, function (data) {
         expect(data.length).toEqual(105779);
       });
     });
     it('gets stats', function() {
       var promise = doc.getStats();
-      waitsForPromise(promise, function (stats) {
+      waitsForPromiseResolved(promise, function (stats) {
         expect(isArray(stats.streamTypes)).toEqual(true);
         expect(isArray(stats.fontTypes)).toEqual(true);
       });
@@ -161,7 +183,7 @@ describe('api', function() {
       });
     });
     var page;
-    waitsForPromise(promise, function(data) {
+    waitsForPromiseResolved(promise, function(data) {
       page = data;
     });
     it('gets page number', function () {
@@ -187,13 +209,13 @@ describe('api', function() {
     });
     it('gets annotations', function () {
       var promise = page.getAnnotations();
-      waitsForPromise(promise, function (data) {
+      waitsForPromiseResolved(promise, function (data) {
         expect(data.length).toEqual(4);
       });
     });
     it('gets text content', function () {
       var promise = page.getTextContent();
-      waitsForPromise(promise, function (data) {
+      waitsForPromiseResolved(promise, function (data) {
         expect(!!data.items).toEqual(true);
         expect(data.items.length).toEqual(7);
         expect(!!data.styles).toEqual(true);
@@ -201,7 +223,7 @@ describe('api', function() {
     });
     it('gets operator list', function() {
       var promise = page.getOperatorList();
-      waitsForPromise(promise, function (oplist) {
+      waitsForPromiseResolved(promise, function (oplist) {
         expect(!!oplist.fnArray).toEqual(true);
         expect(!!oplist.argsArray).toEqual(true);
         expect(oplist.lastChunk).toEqual(true);
diff --git a/web/viewer.js b/web/viewer.js
index ddf3adcc4..ae047c732 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -677,30 +677,27 @@ var PDFView = {
         self.load(pdfDocument, scale);
         self.loading = false;
       },
-      function getDocumentError(message, exception) {
+      function getDocumentError(exception) {
+        var message = exception && exception.message;
         var loadingErrorMessage = mozL10n.get('loading_error', null,
           'An error occurred while loading the PDF.');
 
-        if (exception && exception.name === 'InvalidPDFException') {
+        if (exception instanceof PDFJS.InvalidPDFException) {
           // change error message also for other builds
           loadingErrorMessage = mozL10n.get('invalid_file_error', null,
-                                        'Invalid or corrupted PDF file.');
-//#if B2G
-//        window.alert(loadingErrorMessage);
-//        return window.close();
-//#endif
-        }
-
-        if (exception && exception.name === 'MissingPDFException') {
+                                            'Invalid or corrupted PDF file.');
+        } else if (exception instanceof PDFJS.MissingPDFException) {
           // special message for missing PDF's
           loadingErrorMessage = mozL10n.get('missing_file_error', null,
-                                        'Missing PDF file.');
-
-//#if B2G
-//        window.alert(loadingErrorMessage);
-//        return window.close();
-//#endif
+                                            'Missing PDF file.');
+        } else if (exception instanceof PDFJS.UnexpectedResponseException) {
+          loadingErrorMessage = mozL10n.get('unexpected_response_error', null,
+                                            'Unexpected server response.');
         }
+//#if B2G
+//      window.alert(loadingErrorMessage);
+//      return window.close();
+//#endif
 
         var moreInfo = {
           message: message