Can't log out of forum

[Plantsman]

Can you help please.
Firefox won't allow me to log out of my SMF forum - gives me the following message. 

An Error Has Occurred!
Session verification failed. Please try logging out and back in again, and then try again.

Of course that does not make sense because I cannot log out.  Rebooting the comp does not help.
Logging out of a session on the computer does not help either.

[Plantsman]

Problem solved - thanks

[djstew]

how did you fix it?