I'm a new Lubuntu user, and am in the process of trying to get dvds to play. I have GNOME MPlayer and Dragon Player. I downloaded libdvdread4, no luck. I tried sudo chmod 660 /dev/sr0; chgrp cdrom /dev/sr0, as many people suggested, and even with sudo I got the error message: chgrp: changing group of `/dev/sr0': Operation not permitted. I'm at a loss for what to do next.