The state information is invalid for this page Error

Question

Hi Friends ,

  Am Getting Following Error on my ASP.NET C# Page Button Click event

The state information is invalid for this page and might be corrupted.

 i've Added

if (Request.Browser.Browser == "Firefox")

{
  Response.Cache.SetNoStore();

}


And in Web.Config
viewStateEncryptionMode="Never"


then also am getting error what Problem why this error Occuring to me
Regards....,
R.V.Rajagopalan