First post, although I have been using the free DVDFab since July 07, upgrading to the pay version in May 08. Great product guys !
I am having the same problem as fnsmag with DPG conversion. It either crashes (I have emailed a couple of crash reports off), or as fnsmag says, it gets to 100% then never ends. Looking at the temporary files that are left around at the end of the process, the video files look ok, but the sound files are always empty.
I have tried to convert to DPS using something other than DVDFab (DPGBatch) and that also produces empty sound files (so it might be related to the configuration of whatever DVDFab & DPGBatch are using to do the conversion under the hood (ffmpeg or mencoder ?).
Scouting around the net, the only fix I could see was setting the ffdshow audio decoder configuration for the Mixer, so that the Output speakers configuration was 2/0 - stereo, but I only option I have close to that is 2/0/0 - stereo option