Final Fantasy XI for Xbox...when I try to load it again, it says "Disc is unreadable?" Help!?

i play on ps2 ps3 and pc so dont really know about xbox but why do u need the CD? on the ps2 ps3 and pc you rip it to your HDD i mean you have to rip it to your HDD theres no other way to play, anyways i would think your xbox is f***ed (no surprise there) get a new one or clean the disc or something sorry couldn't of been of more help to ya.