When you try to host an asp site in different apps server to query the sharepoint engine 2003, you may recieve the error
"Error Creating Control - Formdigest1. Failure decoding embedded permission set object"
while using the Formdigest control.
Formdigest controls is to be used in the pages of web application where in you query and update the sharepoint data via object ibrary. Formdigest validates the security of the page while submitting a request.
To make it work, the web apps should be deployed in the same site, i mean in the same context.