I tried backing up Wizard of OZ. When I played back the VOB's in PowerDVD the first VOB didn't start with the movie. It had part of the bonus material at the begining , only 2 minutes worth, but when played in PowerDVD there was no audio for the entire VOB. As soon as the 2nd VOB started sound was restored.

I used DVD2AVI and chose Decode to WAV, when it started the audio format box was empty up to the point where the actual movie started 2mins into VOB1 then it showed the D/D 3/2 blahblah.

When I sourced ranged the video in TMPG to remove that crap at the start it actually cut into the movie audio.
The only way I could get around it was to redo DVD2AVI but set the index mark to where the actual movie started.

Very strange