backed up dvd to dvd

[nalla]

hi all im new to this so i was wandering if someone could help i got hold of some backup dvds the other day and they work fine on my standalone + xbox and my friend wanted to borrow a couple so i said i would burn him one when i had with prassi done on disk to disk it wouldnt work on my m8s dvd but did on mine but the original backup does why is this any help would be much appreciated i also then tried with nero but the same happens.