I just installed Ubuntu 12.04 on a Dell Inspiron 6400 and tried to enable playing of encrypted DVD's, I made sure
libdvdread4is installed and got myself
apt. When I try running it however it tells me
regionset version 0.1 -- reads/sets region code on DVD drives
ERROR: Could not open disc "(null)"!
Please ensure there is a readable CD or DVD in the drive.
I tried this as root, as non-root, with an actual encrypted DVD and also with a "normal" cd with some pictures on it. They both get automatically mounted.