Yeah, that happens to the main page sometimes.
Just go to your browser history and find a thread in another section, and then try going back to the main page.. it should work then.
This forum is literally falling apart... does anyone even maintain it anymore? The PM system is screwed, the quote function doesn't work (unless you force in the [ quote ] tags manually), the search function barely works, many profiles can't be viewed, and the list goes on..