TMPGE Express can't decode audio

Anytime I want to import footage into TMPGE Express (or TMPGE DVD Source Tool) from VOB files, it always tells me that it can't detect a compatible audio stream so it will only rip the video. I've tried extracting the audio separately but I always end up with skewed audio.

I have the AC3 codec installed on my PC, and I can play-back DVD's with no problems (either the DVD disc or VOBs that I've ripped out with DVD Decrypter/DVD Shrink.) It really drives me nuts because sometimes I just want to grab one video segment off a DVD, or I want to write one DVD+R DL with multiple movies on it, and I can't do it.

Any suggestions would be appreciated. Thanks.