Strange Website registering dynamics

I am just shooting in the dark here and don't know if this is Vista related or not but would appreciate any feedback from anyone knowledgable in this area. I am registered with a professional online forum. When I login I get the "Thank you for logging in Aurelian" message box. When the home page appears at the upper right are two blank userid and password text boxes as if I didn't login. When I try to post the site tells me I need to be logged in. I had my user account deleted and registered again with the same result. I was able to login on registering but after logging of got the same dynamic starting back up again. Has anyone else run into this? If so what fixed the problem?. The site admin was able to log in using my username and password so it doesn't appear the problem is from that end. Any help would be appreciated.