The West Wing: Season 2, Disc 4 - I have never seen this protection.

[RSXSpeedDemon]

Ok, I recently purchased the West Wing, Season 2 on DVD. As always, I proceeded to make a backup, and put away the original. Well, I get to disc 4, using DVD Shrink, and it freezes up at 70% giving me the cyclic redundency check error. Again, this is a BRAND NEW disc, with no scratches, smudges, etc. I also tried using DVD Decryptor with the same results. Here's where it gets more interesting. My friend is also a West Wing friend, so I had him bring his season 2, disc 4 over to my house. His disc: perfect condition. Results: Same as mine. Any suggestions? I'm lost on this one. And it's only disc 4 that does it. All other disc's worked fine.

HELP!!!