Did some tinkering and got it work in a hackish roundabout way.
1st- Decrypt the DVD with seperate program.
2: open dvd shrink, but don;t click open disk or open files,
3: click re-author, and navigate to the decrypted files
4: Select the video files you want, BUT DO NOT ATTEMPT TO ADJUST COMPRESSION SETTINGS)
5: Click BACKUP and enjoy, (Preview even works!)
ALTERNATE:
you can skip the decryption step, (as long as you still navigate to the dvd through the re-author button) but dvdshrink will then require you to select automatic compression, and when you try to adjust the compression settings it will crash. So this is only good if you have a disk that doesn't need compression after re-authoring.