A number of Sony customers are reporting problems with several newer Sony "DVD" discs. Why the quotation marks you ask? because they are not designed to be compatible with the DVD-Video standard, so like the Sony CD-like discs that are not designed to the CD Digital Audio specs I'm not sure I can call these things DVDs in good conscience.
Take a look at this Blog for one gentleman's story about his encounter with these discs and Sony support. http://sonystrikesagain.wordpress.com/
So far the list of effected discs is:
Stranger Than Fiction
The Pursuit of Happyness
...but I'm sure we can expect more of these.
My advice is :
Don't buy SONY DVDs
If you must buy them, test in as many DVD players as you can before you lose the reciept and take it back if it fails to work in even 1 tested machine.
If you really want to stick it to them buy, return, repeat. ...as many times as you can. ...and do it at Walmart just to kill two birds with one stone.