Load up MSdash and switch language to any other. Then switch off and on again and go back to ms dash and select original language. Then restart with Forza. Worked for me first time with HDD and DVD backups Good Luck.
Well, I'm not sure if I can help much. But for me, all I did was use Craxion 4.0 and Nero, and it worked perfectly. you might wanna try that.