Hi,

Did you have any luck solving this problem? I'm getting the same error on 
occasion. I also get the following error randomly:

The View State is invalid for this page and might be corrupted.
System.Web
   at System.Web.UI.Page.LoadPageStateFromPersistenceMedium()
   at System.Web.UI.Page.LoadPageViewState()
   at System.Web.UI.Page.ProcessRequestMain()

I think they might be related and also seem to be more frequent when the 
web server is really busy.

Regards
John Farnea

> Hello, 

> I'm getting an internal ASP.NET error in a method called ProcessData as 
f> ollows:-

> Specified cast is not valid. 
.> ..
S> tack Trace: 

> 
[> InvalidCastException: Specified cast is not valid.]
 >   System.Web.UI.Page.ProcessPostData(NameValueCollection postData, 
B> oolean fBeforeLoad) +633
 >   System.Web.UI.Page.ProcessRequestMain() +885

> It's bizarre as we have many aspx pages and we cannot find a pattern to 
t> his problem.

> Has anyone else had this? I would be grateful if you could lend a hand,
M> any thanks!