Actually, it won't even accept the file. I get a popup that says it's an invalid DVD navigation structure.
I even tried to run it through DVD Decrypter to make an ISO file, but that file gets the same popup.
I tried DVDFabDecrypter, and even though I set it for full disk, it only copied something like a 4mb file.
I've used all three of these programs quite a few times over the years, so I'm pretty sure i'm not making a mistake. I think the issue lies with the fact that Roxio was used to create the DVD.
And I even tried it on two machines. This one, which is 64-bit Win7, and a 32-bit WinXP machine.
You can try running it through FixVTS before opening it in DVD Shrink.
In any case, if the main title is in one set of VOB files,each of which can be played individually,(example:VTS_01_1.VOB, VTS_01_2.VOB etc), they can be joined using VOB2MPG and a new DVD reauthored using the likes of DVD Flick without any re-encoding or loss of quality.