"Player to load content" PLEASE HELP!!

I have had this problem for a while now hoping that 343 would fix this problem but it is apparent to me now that it is not gonna happen. When I first got the game, I had no problems I could play the campaign and all multiplayer games just fine. However, after I completed mission 6, “The Composer” the game automatically took me back to the main screen and after I tried to load mission 7, “Midnight”, it responded with “PLAYERS FAILED TO LOAD CONTENT”. Ever since I have been not able to resume my game on campaign but I have been able to play everything else just fine. I did successfully install disk one, and I have redone that many times. IF somebody could provide me with some insight that would be greatly appreciated.

I have a Xbox 360 original elite

I did install the game to my hard drive

I am using a 120 gb HDD hard drive

The load error only happens on Mission 7, “Midnight”