Using "Open files" I've tried opening each of the files that MakeMKV supports (such as HVDVD_TS/HVA00001.VTI) with no success.
Is there something else I need to do?
Here's the complete error log for an attempt.
Debug log started at Wed Apr 02 12:35:59 2014 , written by MakeMKV v1.8.9 win(x64-release)
Using 524544KB for read cache.
001005:0000 MakeMKV v1.8.9 win(x64-release) started
001004:0000 Debug logging enabled, log will be saved as C:\Users\robc/MakeMKV_log.txt
001003:0020 DEBUG: Code 0 at 0O>QZ1K("<&t`:213130168
005010:0000 Failed to open disc
Application exited at Wed Apr 02 12:36:38 2014
FYI- Trying to read the disc directly gets an error on one of the files (even though I can copy the file using other utilities). I tried using InfraRecorder to make an ISO of the directories/files but MakeMKV couldn't open the ISO (I don't know if I made the ISO correctly, I made a "DVD" ISO of about 27 GB

Cheers,
Rob.