In general, almost all DVDs you purchase or rent from the store have encryption embedded them to protect you from copying them. It sounds like a good idea to prevent the piracy. To play back those DVDs, we need the player that could decrypt the encryption back. It’s not problem to play them on Windows operating system, but it is with most Linux operating system such as SuSE 10.1, Debian, etc.
However, we can install the missing bit to enable DVD (with encryption) playback on Linux. Assume you have some media playback such as Totem or Kaffeine (my favorite one), you need to install libdvdcss2, which you can find at:
http://download.videolan.org/pub/libdvdcss/1.2.9/rpm/libdvdcss2-1.2.9-1.i386.rpm. Just download and install it, then try to play the DVD again.