Thanks for the reply and the "forum lesson".
After further investigation I've figured out the problem is with playing the copies with PowerDVD7 on my secondary monitor (Gateway FPD2185W) 21" wide screen. I've had a lot of trouble with using it as a secondary monitor (it doesn't like being 2nd, ).

However, it just started doing that 'skipping' since I originally had it as the primary monitor and I haven't figured out why yet. Mixing wide screen monitors in a multi-monitor setup with a standard 4:3 LCD monitor with the ATI9600 card causes lots of problems but I thought I had them worked out. Gateway says you have to move the EZtune software window over to their monitor to make adjustments but it doesn't seem to make any difference. I suspect the software isn't designed for it to be the secondary monitor unless all monitors are identical.

Anyway the disks play fine on a standalone DVD player and TV.