Install the software:
sudo apt-get install libdvdread4
Do a setup to install libdvdcss2:
sudo /usr/share/doc/libdvdread4/install-css.sh
This gives the good libraries to read or rip DVDs:
fred@linox:~$ dpkg -l | grep dvdcss2
ii libdvdcss2 1.2.10-0.2medibuntu1