I was getting this issue, and finally found a solution that I wanted to post because I had such a hard time figuring out anything about it. But found a lot of people talking about it.
When I was exporting my video clip to use (it never happened on short videos, just longer ones) I always exported quicktime with audio. Obviously having the correct audio specs 48Khz @ 16 bit.
The workaround I found to use, is to create the video and audio seperately. Then put them into your DVD authoring program and merge them together in a timeline...this has worked for me using Sonic DVDit, and for a friend of mine using Avid DVD by Sonic.