having problems reading dual layer dvd's

Hi Guys

I need some help on this question ok I had a guy who burnt me a dvd and the dvd haves a program on it and the program is on dual layer and when i put it into 2 different computers doesnt read the dvd's at all and the other computer i have i put it into a dvd-rw and it still doesnt read what can be wrong here bc i really need to know this answer asp

not all dvd drives/players play duallayer disks

well see what is funny both of my dvd players says it can read dual layer dvds