getting "Invalid postback or callback argument" error when click on the Image button

In my application, I have videos with an image. When I click on any video, it is showing this message:

Invalid postback or callback argument. Event validation is enabled using 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. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.

I placed the EnableEventValidation="true" both in web.config in that particular page but it is giving same error.

simple place your method, that fetch the data from the database in "ispostback" method then it will not give any error. i got the same problem i place the code in ispostback method in page load it is working fine.