I can't rip an already burned game, Why?

[soundfx4]

Hi, I was going to copy one of my already burned games to give to a friend, but when I ripped it with DJ, I couldnt convert it to a bin. It kept saying "invalid format". What the hell is it talking about? I tried ripping it 2 or 3 times, but everytime the same thing, why is it doing this? Please let me know, thanks