well, what i ended up doing was starting the backup and then finishing it using a file manager. there are over 19000 files to copy, but you only really need the usdir. i would suggest that you try doing it with a file manager if you run into problems. ive got it on my ps3. to back up using file manager, open the location of the started backup (/devhdd0/games/blus30566 or whatever it is for the game/backup manager you were using) on one side, open the bluray disk in the drive on the other side and copy the usdir and other things over from the disk in the drive to the backup location.