Im pretty sure this isn't a backup problem, but I'm using the game backed up onto a dvd-r. I get to the part where you're supposed to tap A repeatedly to pull this green roof off, but tapping A does nothing, it doesn't freeze, i just can't beat that mission. I tried restarting but no good. At that point I can't continue the game because I can't do the special training either since it wont show up. any help appreciated.