Index: UI/Scheduler/UIxCalMainActions.m
--- UI/Scheduler/UIxCalMainActions.m.orig
+++ UI/Scheduler/UIxCalMainActions.m
@@ -90,7 +90,7 @@
   if (ex)
     {
       httpStatus = 500;
-      jsonResponse = [NSDictionary dictionaryWithObjectsAndKeys:
+      jsonResponse = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                                      @"failure", @"status",
                                    [ex reason], @"message",
                                    nil];
