I ran in to a similar problem a while back, but my data was duplicating. If the user hadn't filled out all the requested fields and the name field was John Doe, then it was coming back John DoeJohn Doe after a second submission. Might FireFox's "remember stuff" option be doing that? If so, do you have any idea of a workaround?

This was a self referencing CGI script if that makes a difference.