Ugh. I've been tangling with this problem for days.
According to what I'm reading on the UBB.threads developer forum, UBB.threads does not play nice with the newest versions of PHP and with the security modules installed on this new server I've rolled back to an earlier version of PHP and tried to work around the security mods problem. I hope (fingers crossed) that fixes the slowness and the Internal Server Error problems.
If it doesn't, I'll keep tinkering. I'd hate to have to disable the added security modules, but if I have to, I have to.
