Index: /CKEditor/trunk/_source/plugins/dialog/plugin.js
===================================================================
--- /CKEditor/trunk/_source/plugins/dialog/plugin.js	(revision 6406)
+++ /CKEditor/trunk/_source/plugins/dialog/plugin.js	(revision 6407)
@@ -2958,5 +2958,8 @@
 				}
 				else if ( dialogDefinitions == 'failed' )
+				{
+					hideCover();
 					throw new Error( '[CKEDITOR.dialog.openDialog] Dialog "' + dialogName + '" failed when loading definition.' );
+				}
 
 				var me = this;