I have the same problem with my forums:
http://xcit.gotdns.com/smf/ (I'm a new member, so not sure if I can't post links...)
I recently tried to add the Google Analytics code to the bottom of the main index.php and I think this was what brought up the problem. I kept seeing this at the top of the page: , so I got rid of the code. I still kept getting these strange symbols when using the forums and still get the verification error.
I checked index.php to make sure there was no code above <?php or below ?>.
Can anyone help?