The link URL itself was missing the u=USERID part. I added that, and now the link doesn't give you an error, but it still doesn't log you out. Fun fun fun.

EDIT: To log out, you need to manually delete all cookies from eyesonff.com, www.eyesonff.com, forums.eyesonff.com, and any other variation of eyesonff.com that you can find. In Firefox, that's Edit, Preferences, Privacy, Cookies, View Cookies. Then close your browser and open it back up and you should be logged out. After doing that, the Log Out link should log you out normally in the future.