IP Address error

For the last week or so, I've been getting a strange error where directly visiting

http://forum.gsplayers.com

redirects me to

http://forum.gsplayers.com/cgi-sys/defaultwebpage.cgi

which gives me an error message about how either "The IP address has changed", "There has been a server misconfiguration", or "The site may have been moved to a different server". Visiting any of the subpages of the site (e.g. http://forum.gsplayers.com/forum.php ) works just fine (so the forums are still completely usable for me except for this one page). Clearing the DNS Cache didn't fix anything.

Any idea what might be causing this (either on the forum's end or my end)?