migidymike,

Not sure I'm going to have the right answer for you, but I know how frustrating these things can sometimes be. Maybe I can point you in the right direction.

I had similar problems with a DVD I made in Encore DVD. Everything previewed fine, but all of my video had no sound when I put it in my DVD player. The only areas of my DVD that had any audio at all were in my menus, where I added background music. It took me a while to figure out that this was because my menus and their music were being transcoded when I burned the DVD, where my regular video files were not (because they were already mpeg2). I don't know a lot about this, but I do know that MY DVD player doesn't like mpeg audio. Once the video files were transcoded, new audio files were created (these were AC3, I think?) Audio and video worked just fine!

You may not be getting sound to play back because your DVD player needs a certain audio format. Hope this helps.