I have recently made 30 sec spots for two different clients and gave them approval DVDs authored in iDVD. They both told me that when they play the DVDs on their PCs they see the video fine but there is no audio. Both DVDS play fine, audio and video, on my set top DVD player and on my G4. I haven't run into this before. Both clients think that they have the most recent software for their PCs. I had one client play her DVD on her home system and it played fine there.
I just dragged the exported movie from FCP and dropped it into iDVD... so whatever the default, in iDVD, is. This was meant as a "quick and dirty" approval solution. I have made other approval DVDs during this same timeframe and have had no problems. And the one that is giving my client "problems" plays fine everywhere I've tried it.
This has happened with two seperate clients in the last month.