Mitch

Can anyone help me with a little iDVD problem. I shared an iMovie with iDVD, the movie played fine in both iMovie and iDVD, I burnt movie to a dvd disk. When I play the burnt dvd in my dvd machine the sound is about a second before the picture. I have tried reburning it, re-sharing it and reburning it but neither of these helped. I live in Australia and my video camera was purchased here. When I first got my Mac (4 months ago) I made loads of iMovies but when they were burnt and played in my dvd played they jumped, skipped and froze. I rang Applecare and they said I need an upgrade (who would have thought that the 'latest' machine would be outdated by the time I got it home!!) I got the upgrade but was them told I could not use any clips from any previous iMovies, but if I retrieved these clips from 'package contents' saved them to a folder on the desktop they could then used to remake the original iMovies. I have done this and as I said they play fine in iMovie and iDVD but I have this sound problem and Applecare don't really know how to fix it. Can anyone help me?
Mitch