HELP! i keep getting an error when trying to post a thread!HELP

[1337asusual]

whenever i try to post on my forums i get this error: Authorisation code mismatch. Are you accessing this function correctly? Please go back and try again.

Also log out doesn't work properly either: Your user ID could not be verified to log you out. This may have been because a malicious Javascript was attempting to log you out automatically. If you intended to logout, please click the Logout button at the top menu.

[lufbra]

Please read the pinned posts above!

[1337asusual]

didn't help

[1337asusual]

i just need an updated theme i guess thats all

[sluggy]

I had the same problem and it was resolved here.
http://community.mybboard.net/showthread.php?tid=28428

Please remember before you do anything always back up your forums and themes also your database so if you make a mess it can be easily restored.