Game wont work but it seems good cond. and drive recognise it

I have a backup I have'nt played in months

when inserting the game disc evox recognize it good
also I can back it up to my pc ( all files )
(too bad I can't reburn it because I have no DVD burner)

but when I try to play it
appears the dirty disc message in the screen

I know is not the disc
because if it were dirty
my xbox or evox could'nt recognise it as a game

what can be the problem??

xbox live updates?

that's all I can think off now
cause the game is in great condition

somebody with the same problem as me?