Backup movie DVD's now not playing on Mac



I can’t seem to figure out why, but all of asudden my Mac (G5 PowerMac running Panther) won’t play my backup DVD’s that it had no problem playing a few month earlier. The drive is fine because regular DVD’s play on it, and the backups are all fine since they play in my PS2 and on my roomates computer.

I’ve tried downloading codec packs, which did nothing and I’ve removed and reinstalled Mac’s DVD player. I’m at a loss on what to try next, and I like watching tv shows on my Mac while I work so this is really beginning to suck.

Any help would be appreciated.