Solution To run Time error

Hello,
          I have used multiview control and in that i used grid view and formview. I am using objectdatasource to fill the data.
     While i am editing at first time i didn get any problem. After that again i clicked on edit button of grid. At that i a getting the following error. 
Error: Failed to load viewstate.  The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request.
Please tell me the solution. It is urgent.
 
Thanks,