I have a similar problem with backups of games that I've made. When I first put them into my console they wont read, I get the "Open Tray" message down the bottom of the dash. I have a Sony DRU-700A burner and I think it's what is causing problems, so i'm buying a Pioneer 111d. Anyways this is what I did and it's worked for me so I suggest to have a go and see how you go. I put the disc in and when I see the "Open Tray" at the bottom of the dash, I open the tray and then I close it and let it try and read the backup again. I sometimes have to eject and reload the disc up to 10 times before it finally loads. Here's the strange thing though. Once the game loads once it loads a lot easier the next time you put it your console. This only works for me until I turn my 360 off and then I have to eject and reload the disc all over again. It's a pain but it works for me and it might work for you too. Try it and see if works for you. I think the reason happens to me is because my burner isn't making a real good burn and once the 360 finds where it needs to start reading the disc it finds it easier to read it. Sorry about the length of the reply.