If you still have the encoded mpeg2 please run it through the Bitrate Viewer:
http://www.tecoltd.com/bitratev.htm
See if it does in fact cross over the 8mbps max you had set. DVD Studio Pro should not mux if it is too high, but it may be right at the maximum tolerance and thus added with your audio may be having problems in some players. What type of audio are you using? PCM WAV or AC3? Just a thought, not saying this is the issue. Something to try though while you are waiting from a response from your replicator.
-Luke
