The last post in the thread "Hello TLR Users" on teh Twin Lens Reflex forum appears to have some sort of malicious script in it. When you try to display the post using IE (or even open the thread, if you haven't read the post yet), a modal dialog box with the message "I think you are gay" pops up, and when you close it another one opens. This goes on, seemingly forever. The only way for the user to resolve the problem is to terminate the IE session via "Task Manager" in Windows.
Please remove the offending post. Also, notice that it was submitted by "Anonymous", so you might want to reconsider allowing anonymous postings, or what you allow anonymous posters to do (like upload files, use HTML, etc.)