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. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request.

Has anyone ran into this?  It is kinda getting annoying to some of the customers, cause they write a long blog post and then hit the "post" and the error occurs (sometimes).  Then the post is lost.

Anyone have any suggestions?

Thanks!
Gary