I have been trying to burn a .cdr file to a dual layer dvd using Disk Utility. I got it to work once, but I tried four times. I think that it must be very sensitive or something, because I can't figure out any other factor that affects it. Has anybody else run into this problem, and if so, what's your solution? I think it may have to do with vibrations of the disk drive or something, but I would be lying if I said I knew that for sure...