You said you were using "burner software" to encode. Is this Nero by any chance? The problem you mentioned has been reported when people use Nero to encode. The fix is to use another encoder, such as TMPGenc. Is your AVI in sync before encoding? If so, it's definitely your encoding software. You have a couple of ugly options.
1) Lusifer has had some luck shrinking and streching audio with an audio editor to get stuff back in sync.
2) You could use MPEG2VCR (
http://www.womble.com) which is a MPEG-1/2 video editor. If you demux your encoded file, you can move the audio forwards or backwards in the mux until you get it in sync. It takes a lot of trial and error, but if the sync isn't too bad, it does work.