Recently, I installed a dual-boot OS on a brand-new laptop, absolutely fresh system, no OS, no formatted disc. I started with Microsoft XP and after the basic install was complete, I added vlc-0.9.9 to test DVD playback. Surprise: I did not work. Although vlc should be able to playback a DVD without any further decryption drivers, DVD software or costly add-ons, menus were a garbled mess of half-way decompressed video. The DVD was an original, nothing esoteric as a burned DVD or the like. Next I tried a few other DVDs with mixed results, some played a bit of the menu video and sound, some rejected playback altogether.
My first idea was a broken drive - but on a mint new PC? After reading a few forum posts on the net I actually thought about cleaning the lens, but thank god I didn't (you will never get a lens clean as it was after manufacture-quality-control-unboxing...). Fiddling a bit around with Window's right-click menu > Drive Properties, I noticed that on the "DVD-Region" tab no region was set.
A bit more research on the net brought me to this enlighting post on the Ubuntu forum, which seconds what I found out that same minute myself. Set a region for the drive and magically all problems are gone! As it seems, my OS-free system had been shipped with an undefined-region DVD drive. After the install, I oversaw this fact and the drive produced errors on the hardware-firmware level, before it reached vlc. The same is true for Linux systems - so the next time your brand new DVD drive produces errors, check the region-setting first!