I made a typo in the cookie domain, I corrected it now (I hope) thanks for telling!
Try login out and then login on the forums again, then go to the main website and see if you are logged in with your forum account on the main site, if you are the message should be gone.
If the gallery says you aren't logged, when you are, then please tell me (IMG:
style_emoticons/default/smile.gif)