I found the first 20 minutes of (I think) the second episode on disc 2 of grahamb's season 3 boxset completely unplayable. Lots of coding errors and it crashed the DVD player at one point. The discs seemed well seated in the box though, and I couldn't see any scratches (which given the way CDs and DVDs are encoded *shouldn't* be that much of a problem anyway) so I suspect it's just a poor quality pressing. I had similar problems on a couple of the X Files discs too.