Fixed developer errors storing invalid error objects

web/templates/head.html

@@ -98,7 +98,7 @@
             });
 
             if (window.mm_config.EnableDeveloper === 'true') {
-                window.ErrorStore.storeLastError('DEVELOPER MODE: A javascript error has occured.  Please use the javascript console to capture and report the error (row: ' + line + ' col: ' + column + ').');
+                window.ErrorStore.storeLastError({message: 'DEVELOPER MODE: A javascript error has occured.  Please use the javascript console to capture and report the error (row: ' + line + ' col: ' + column + ').'});
                 window.ErrorStore.emitChange();
             }
         }