We know DVD has 6 regions.1: North America; U.S. territories; Bermuda 2: Europe; Western Asia; Kingdom of the Netherlands etc. 3: East and Southeast Asia; 4: Oceania; Central and South America; Caribbean; Mexico; 5: Africa, Central and South Asia, Belarus, India, Mongolia, North Korea, Russia, Ukraine; 6: Mainland China.
Most commercial DVDs use encryption that keeps them locked to one or more "region codes," meaning the discs you pick up in other continents usually won't play on an American DVD player.
Although laptop DVD drives are technologically capable of playing any DVD, they force you to switch among region settings to play imported discs. Try switching this setting more than a fixed number of times (five over the entire life span of the computer), and the setting will be locked forever.
For the free VLC player so far only support to Mac OS X 10.5.4, if your Mac has updated to 10.7 Lion OS, then you can use Mac DVD Ripper to solve the problem by converting DVD to other video formats for playing on iTunes, QuickTime, Apple TV etc.
mactheripper lion