Steve,

You may be having a scsi-emulation issue, however, if you can mount the drive and otherwise use it, I dont *think* this is the issue....

For one thing, you will need a version of decss for debian to be able to read encrypted DVD's. I would also suggest you look into installing mplayer as well. Does a better job (IMHO) of dealing with DVD's and has a more intuitive interface.

However, my favorite and easiest solution is that you use another "live cd" linux distribution called LinuxConsole. It lets you view, rip, and otherwise enjoy your legally purchased / rented DVD's and has a plethora of other goodies on it.

You can check this french beautie out at

http://linuxconsole.free.fr/

Good luck