Hmm. It works fine here. I should clarify that you need to restart IE. Here's the proper approach:
  1. Click Log out [ username ] at the top of the forums.
  2. From Internet Explorer, go to Tools --> Internet Options... Go to the General tab and select Delete Cookies... and then OK.
  3. Close Internet Explorer.
  4. Restart Internet Explorer.
  5. Log into the forums (check "Log me on automatically each visit" if desired).
Hope this helps.