Unable to Mark Forums Read

[Captain Sureshot]

When I click on the Mark Forums Read link at the bottom of the main forum page I get this message:

vBulletin Message
Your submission could not be processed because a security token was invalid.

If this occurred unexpectedly, please inform the administrator and describe the action you performed before you received this error.

I can mark an individual forum as read using the drop down menu near the top of each forum. I am using Firefox v3.6.3