DVD backups - final chapters skipping - why?

[weimeraner]

I use a Pioneer 105 DVD writer with DVD X Copy and DVD Cloner (fully registered versions) to backup my DVD movies onto DVD-r disks.

Most movies have until now copied perfectly, split onto two DVDs where necessary.

Recently, e.g. with Starwars episode 2 and Minoruty report, when I play my backup disk 1 on my Sony DAV-S3000 standalone DVD player, the film plays fine all the way until the final few chapters on the disk. When it gets to the final 3 or 4 it skips chapters every 2 or 3 seconds. This does not happen on my PC DVD player.

Other films play perfectly on my Sony DVD player, so why don't these two most recent films? It happens with copies made using both DVD X Copy and DVD Cloner. Do these software programmes have faults, or is this some new kind of protection on the original discs?

Any advice will be most gratefully received!!