Mass Effect clean disk error xbox 360

I opened my NIB copy of Mass Effect 1, put the disk in my xbox and made it to the first citadel mission (in between anderson and rapid transit to choras den). At the loading screen during rts i get the dirty disk error and tells me to clean it. Disk is new with no scratches. Have tried it in 3 different consoles (each with different upgrades, one of which is only 4 mos. old) and same thing... any suggestions?