Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
So far, I'm passing it off as a hardware problem with the drive. We know the problem the problem is nothing to do with the disc. I have read a few forums about people having issues with their slot-loading DVD drive in their MacBook/MacBook Pros with the sympton of them not being able to read discs properly.

If I come up with anything, I'll let you know. I feel like that I'm going to have to stand outside until I get struck by lightening before I work out the problem.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.