Few suggestions:
1) Try burning slower and with a large (400 MB) dummy file (doesn't matter what the file is
2) Use DVD+or-R media if you can
3) If these don't work or are not feasible, keep restarting!
Good luck, took me about 15 tries with my DVD+R (with the original DVD drive) and CD-RW never worked for me. Have fun with your newly modded xbox!
