Strangely corrupt VOB files

This is mostly a post-authoring question... as I am trying to pull video off a disc I mastered a few years ago.

I was trying to extract a DVD I made to MPEG or MOV files using MPEG Streamclip on my Mac. It would get near the end and conk out with a Read Error. I tried it on multiple Macs and got the same thing.

I did notice it was scratched a little, so I figured it was that. But I contacted a friend who I had given a copy to and asked to drop by with my MacBook so I could rip it.

When I got there, he had already just copied the VIDEO_TS folder to the desktop of his Windows laptop. So I just put a blank DVD-R into his drive and copied the VIDEO_TS folder to the root of the blank disc and burned.

The resultant disc seemed to play fine. But when I tried to extract again using MPEG Streamclip, it conked out with a Read Error again in pretty much the same spot. The funny thing is, if I try to copy the VIDEO_TS folder off this newly burned disc to the desktop of my MacBook, the basic file copy in Finder fails, roughly around the same percentage through as it did in Streamclip. That says to me it's not an MPEG-specific issue.

Thoughts?