If anything, gnome-mplayer is worse as even if you tell it to use /dev/sr0, it will still look for /dev/dvd and not work while mplayer will work. Fixing mplayer will probably not resolve the gnome-mplayer problem. Both are default apps in Ubuntu & derivatives. It is important to fix both. Sorry!
BOTH gnome-mplayer & mplayer have a problem.
If anything, gnome-mplayer is worse as even if you tell it to use /dev/sr0, it will still look for /dev/dvd and not work while mplayer will work. Fixing mplayer will probably not resolve the gnome-mplayer problem. Both are default apps in Ubuntu & derivatives. It is important to fix both. Sorry!
Thanks.