FullCalendar not Working in CakePHP 1.2.5 with jQuery 1.4.1

FullCalendar not Working in CakePHP 1.2.5 with jQuery 1.4.1

I am trying to fetch the events data through a URL which will return JSON data.
The same code is working with jQuery 1.3.2 but not with jQuery 1.4.1

I am getting this error in FireBug console

a is undefined
for (var i=0; i<a.length; i++){\n                                          fullcalendar.js (line 369)

I am getting the JSON data as I can check it in response header of FireBug
jQuery 1.4.1 imposes strict JSON parsing
I am not sure whether it is the issue.

I have kept the FullCalendar example in apache webroot.
If I use "/fullcalendar/examples/json-events.php" for events instead of my CakePHP AJAX url "/myCake/calendars/get_events" it is working for jQuery 1.4.1.
But if I inlude the same code in "/fullcalendar/examples/json-events.php" in my CakePHP get_events.ctp file which generates the same JSON, it is giving the same error with jQuery 1.4.1

If anybody has encountered the same problem and found a solution or work around, it will be very helpfull if you share your experience.