I have only a combination CD/DVD burner, which Puppy sees as /dev/hdc. SCSI emulation is switched off.
When I open Gxine and try to play a DVD by clicking "DVD" in the drop-down menu from "File," it says "xine engine failed to start. Unknown error." Beneath that it says "Read error from /dev/dvd". Looking in /dev, I find that /dev/dvd is a symbolic link to /dev/scd0.
I have tried changing the dvd_device in Gxine's "File->Preferences->input" but the changes don't stick, and anyway I don't really know what to put there.