<pages enableEventValidation="true"/> error

[cognos s]

I ajaxified an exisiting page using radajaxmanager. Primarily, the page is divided into two sections.
Student section and Classes Section. When I click a button "Add Student" a "student panel" is made visible which has bunch of controls in it.
Similarily, the classes section has "add class" button which on click shows "classes panel".

The problem is when the student panel is visible and I click "add class" button I get the following error.

"Invalid postback or callback argument.  Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> in a page.  For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them."

When the student panel is hidden and I click "add class" button, classes panel is rendered correctly. I only get this error when the other panel is already visible on the page.

Any ideas?

[cognos s]

I got it working. nvm