Sometime Second Cascading Drop Down List Gives "Method Error 500" Error

Hi Friends,

I have state and disrict cascading drop down for my site http://www.coursesworld.in. It is working fine in mozilla, chrome and IE.

My problem is sometimes in "IE 8" I am getting Error in District DropDownList as [Method Error 500] when I change State DropDrownList. And sometimes it's woking fine. Why I am getting such weird error? This problem I am not finding in Mozilla and Chorme but in IE 8 it happens.

To see this issue just visit http://www.coursesworld.in and click on Universities.

Can you please give me the solution....

Thanks is Advance.

Regards,
Sushil Patil