Brawl"disk can not be read" error?

I downloaded the Super Smash bros Brawl ROM available on this website and when i fired it up it looked good up at first. The game asked me if it wanted to create new save data which i said yes to obviously but from there i got an error message stating that the disk could not be read. No matter which option I select on the error message it takes me to the games"an error has occurred screen" and it doesnt let me past. Not super good with computers here so i would appreciate the help on resolving this.