Weird. It works on FF from a different computer? Did CC modify your vBulletin recently? I don’t do prefetching or anything else, so maybe a modification on your end conflicted with an extension of mine…
No problem here with FF 1.5. What extensions are you running when you’re having problems? Try disabling them and accessing CC. Are you having problems with other sites too (especially with other vBulletin boards), or just with this one?