www.makemkv.com

I've had this same issue on all of these releases from Mill Creek. Any of the bonus features that are in SD (720x480) all come up with lots of error messages like these:

AV sync issue in stream 0 at 0:00:33.733 : video frame timecode differs by -133.466ms
AV sync issue in stream 0 at 0:00:33.733 : too many video frames with invalid timecodes, future messages will be suppressed

They do save successfully, but playback is messed up. The audio isn't synced right and the video stutters so much that's it's unwatchable. It's been the same problem on all the releases mentioned (Rescue Me, Community, Happy Endings). They playback fine if I run them through Cyberlink PowerDVD, but I haven't found a way to rip them so I can simply add them to Plex and not have to keep re-inserting my discs all the time.