diff --git a/src/core.js b/src/core.js
index 4c262b2d7..785654cdb 100644
--- a/src/core.js
+++ b/src/core.js
@@ -137,6 +137,10 @@ var Page = (function PageClosure() {
       var self = this;
       var promise = new Promise();
 
+      function reject(e) {
+        promise.reject(e);
+      }
+
       var pageListPromise = new Promise();
 
       var pdfManager = this.pdfManager;
@@ -150,7 +154,7 @@ var Page = (function PageClosure() {
             this.idCounters);
 
       var dataPromises = Promise.all(
-          [contentStreamPromise, resourcesPromise]);
+          [contentStreamPromise, resourcesPromise], reject);
       dataPromises.then(function(data) {
         var contentStream = data[0];
         var resources = data[1];
@@ -161,7 +165,8 @@ var Page = (function PageClosure() {
             opListPromise.then(function(data) {
               pageListPromise.resolve(data);
             });
-          }
+          },
+          reject
         );
       });
 
@@ -195,9 +200,9 @@ var Page = (function PageClosure() {
             PartialEvaluator.optimizeQueue(pageQueue);
 
             promise.resolve(pageData);
-          });
-        });
-      });
+          }, reject);
+        }, reject);
+      }, reject);
 
       return promise;
     },
diff --git a/src/util.js b/src/util.js
index 0ee9ef6ed..8955a5001 100644
--- a/src/util.js
+++ b/src/util.js
@@ -694,16 +694,26 @@ var Promise = PDFJS.Promise = (function PromiseClosure() {
       deferred.resolve(results);
       return deferred;
     }
+    function reject(reason) {
+      if (deferred.isRejected) {
+        return;
+      }
+      results = [];
+      deferred.reject(reason);
+    }
     for (var i = 0, ii = promises.length; i < ii; ++i) {
       var promise = promises[i];
       promise.then((function(i) {
         return function(value) {
+          if (deferred.isRejected) {
+            return;
+          }
           results[i] = value;
           unresolved--;
           if (unresolved === 0)
             deferred.resolve(results);
         };
-      })(i));
+      })(i), reject);
     }
     return deferred;
   };
@@ -784,12 +794,8 @@ var Promise = PDFJS.Promise = (function PromiseClosure() {
     },
 
     then: function Promise_then(callback, errback, progressback) {
-      if (!callback) {
-        error('Requiring callback' + this.name);
-      }
-
       // If the promise is already resolved, call the callback directly.
-      if (this.isResolved) {
+      if (this.isResolved && callback) {
         var data = this.data;
         callback.call(null, data);
       } else if (this.isRejected && errback) {
@@ -797,9 +803,12 @@ var Promise = PDFJS.Promise = (function PromiseClosure() {
         var exception = this.exception;
         errback.call(null, error, exception);
       } else {
-        this.callbacks.push(callback);
-        if (errback)
+        if (callback) {
+          this.callbacks.push(callback);
+        }
+        if (errback) {
           this.errbacks.push(errback);
+        }
       }
 
       if (progressback)
diff --git a/src/worker.js b/src/worker.js
index 5209c6015..8e556c85a 100644
--- a/src/worker.js
+++ b/src/worker.js
@@ -137,7 +137,8 @@ var WorkerMessageHandler = {
             javaScript: results[6]
           };
           loadDocumentPromise.resolve(doc);
-        });
+        },
+        parseFailure);
       };
 
       var parseFailure = function parseFailure(e) {
@@ -261,7 +262,7 @@ var WorkerMessageHandler = {
 
       var onSuccess = function(doc) {
         handler.send('GetDoc', { pdfInfo: doc });
-        pdfManager.ensureModel('traversePages', []);
+        pdfManager.ensureModel('traversePages', []).then(null, onFailure);
       };
 
       var onFailure = function(e) {