In the right pane of the site, where it tells you if you have messages or new responses to threads, there is one thread that will not go away. I click on it and go to the page, but it is still there. Also, the last user to post (according to the main page) doesn't show up when I click on the thread. What's going on here?
It seems like that last post was removed by the Moderators for some reason and because you can't read it, the system keeps reminding you about it. Try posting yourself and see if that corrects the problem after you close te thread, reopen it and read your own post.