Error: Invalid postback or callback argument when I use "updatepanel"

Dear All,,
Kindly check my issue:
I have been dealing with this bug for about two weeks and I NEED to solve it.
I have read every article available over the internet,but no result ,still the bug appears.I'm sure the solution is going to be very silly.I have a gridview inside an updatepanel,While sorting or paging I don't get the error,I only get it when I click on an Imagebutton or Linkbutton(Delete,Update):
So please check it:

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

Stack Trace:

[ArgumentException: 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.  If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.]
   System.Web.UI.ClientScriptManager.ValidateEvent(String uniqueId, String argument) +340
   System.Web.UI.Control.ValidateEvent(String uniqueID, String eventArgument) +69
   System.Web.UI.WebControls.CheckBox.LoadPostData(String postDataKey, NameValueCollection postCollection) +74
   System.Web.UI.WebControls.CheckBox.System.Web.UI.IPostBackDataHandler.LoadPostData(String postDataKey, NameValueCollection postCollection) +13
   System.Web.UI.Page.ProcessPostData(NameValueCollection postData, Boolean fBeforeLoad) +357
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1768

Tags: C#, Ajax, ASP.NET