I totaly feel your pain. Fallout is a huge percentage in my life haha, but this bug is Rediculious. Its wasting time and money. BOO BETHESDA,youve let us down
Just talked to one member that did the following. He deleted Dead Money, cleared the Xbox 360 system cache, then redownloaded the the DLC, received the game update again, and then started the quest again. It was reported that it worked this time around.
If you're still experiencing issues. You might want to give this a shot