I had PathPlayer set to 'always'. I tried it with the other 2 settings and DVDFab fails the same way. It exits as soon as it starts analyzing the disc. This is in Main Movie mode.
I tried Full Copy mode also (PathPlayer disabled). In that case, it does a first scan and then the progress dialog goes away, then it starts a second scan and then exits.
I also tried disc #2 and it fails in the same way.