In my case, I ran a program called prime95. This program checks your processor for errors, and lo and behold, it failed miserably. So I grabbed another processor, from a duplicate machine, and now the video conversion works. And when I ran prime95 on the new processor, it didn't fail.
It's just awful funny though, that I had absolutely no problems with my system, except this video conversion thing.
Since putting in the new processor, I've had no problems with dvdfab.