DVD drive issue and permissions repair

Forgive me if I'm combining two issues in this posting. If they are not related I can separate them out.

I don't know if my drive is going, but I have a DVD for a tv show that I wanted to watch on my Macbook Pro running Snow Leopard (latest patches). For a while now I've had to keep reinserting the disc because it's not registering. I put it in, and can hear mechanisms, then it spits it back out.

I watched one disc, ejected it then tried to play another and it just would not load.

I thought of checking disk permissions, thinking maybe the OS had some permissions problems that may be preventing it from reliably reading the disc. The disk utility reported a number of permissions errors and owner errors, so I repaired the permissions and it reported that it was completed successfully. I thought I'd run the verify permissions again, just to make sure the errors had really been repaired, and they're still there - some of them were gone, but there were others reported. I ran the repair and verify a number of times now and nothing's changed.

My questions:

1. Could the problem I'm seeing with my DVD drive be related to permissions of some of the system files?

2. Do I have anything to worry about with the disk permissions not appearing to be repaired?

3. Would I gain anything by booting to install media and running the verify and repair from there?

Thanks much in advance!