I have just recently purchased a new Xbox 360 because my old one had broken. I originally had a profile called "insanechipmunkz", but now i use a different one. I use now "King Jakabes" and "Altomphion" for my gamertags. Anything that I downloaded on one profile doesn't work on the other. I did download the DLC on the other Xbox, but even the DLC that I downloaded on the new Xbox doesn't work. I tried the License Migration thing but that still didn't work. The problem is mainly with Rock Band DLC, but other games like Guitar Hero and Halo do this too.