Don't know if this would be a solution but ...
sudo apt-get install regionset
In a console as root type regionset.
If you get an error it's not installed.
Please be aware that most drives limit you to about 5 changes (regionset should tell you how many you have left - just issue the command as root).
If you plan to watch foreign DVDs, it would be best to have a secondary external DVD drive, and have it set to a different region to the 'main' DVD in your machine.
To set or change your DVD drives region, put any disc into your drive, and in a console as root type regionset.
Then simply select the relevant region code.
Here is the list of region codes and which countries they cover:
RC1 = North America (USA and Canada)
RC2 = Europe, Middle East, South Africa and Japan
RC3 = Southeast Asia, Taiwan, Korea
RC4 = Latin America, Australia, New Zealand
RC5 = Former Soviet Union (Russia, Ukraine, etc.), rest of Africa, India
RC6 = China