Nope it could also mean the DVD has degraded, and they all do some a lot faster than others, due to a number of reasons with Verb though I would say improper storage. How are you storing the discs?
Try it again under windows and leave it to do it, do not cancel if this hs problems you will get errors. Also do you have access to a DVD-ROM? Some writers make losey readers and may baulk at a problem area where a DVD-ROM may read it and get it off.
EDIT: Also there have been times when I have had an error when I try to move the entire contents of the disc in one go and it tells me which file it has the problem with, and when I just copy and paste that one file it works in the majority of cases.