Odd out-of-sync audio problem

I have been using TMPGEnc Authoring Works for some time now and have no problems with it and the few times where I had an project that had the audio of sync I always traced it back to the original file.

But last night I burned a very old AVI that looked fine it's raw form. It even looked fine in the simulation feature that TMPGEnc has that shows you what the burn will look like. But still when I played the disc back in Media Player Classic and in my home DVD machine, the audio was out of sync some. So that tells me that must have been done during the burn process.

I know sometimes not having the right codec is a factor, but I've got all of Sharks codecs installed...XViD, FFDShow, AC3, plus Divx 7. Normally I put the projects right straight to DVD-R but lately I've been putting many of them on DVD-RW and then re-using that same disc over and over for awhile, so I don't know if that could be a factor.

Also now I'm wondering about the media I use. I have been using TDK DVD+R's and RW's, but maybe I've been getting some bad ones and should switch to Verbatim.

Your thoughts are appreciated.