Try DVD Santa,i've taken a couple avi movie's and converted them no problem,The only thing is it will take a good couple of hour's to convert them over.
Well right now i'm using a celeron 2.4ghz and i take divx movie's and convert them and it take's me 4 hour's or so to do it,But it might work a little faster for you,It all depend's on how big the original file is that you want to convert.