Dungeon Siege disk 1 iso problems

I acquired iso files of disk 1 and 2 for Dungeon Siege. I have made 3 coasters trying to get CD1 to work. Since I didnt make the iso file is it safe to assume that its bad and not my burn process?? Im useing Nero with Plextor 12x40x12A. Im just selecting burn image and changing the block size to 2352 because is says the block size 2048 is incorrect. It burns fine and installs fine but I get a corrupted file.