I am sorry for all the problems you're having with this script.. It was something I wrote a long time ago and I don't have the time to fix all the numerous bugs that have been appearing with the new PHP and MySQL releases.
I'm sure some of the problems (like the duplicated threads) are caused by new versions of PHP and/or MySQL.... The first releases of this script didn't have such problems... I took a look to the code a few days ago but I can't find the problem... It requires some more testing and some more time, and that's something I don't have right now
I'd be very happy if some of you guys can improve this script until Jelsoft officially releases something like this for vB2 and vB3.
Right now I can't take care of this script, even though I would love to fix it and post it here for the benefit of you.