Yes, it does sound cookie-related...
To make sure you have cookies properly set on your system, go to the "Preferences" link for each main Forum (Miles, Travel, Dining, Airports), delete your existing FT cookies using the link on that page, then set new ones.
Here's the links to each of the main Forum preference areas:
http://www.flyertalk.com/forumcgi/ub...ction=setprefs
http://www.flyertalk.com/travel/fttr...ction=setprefs
http://www.flyertalk.com/dining/ftdi...ction=setprefs
http://www.flyertalk.com/airports/ft...ction=setprefs