Paul Smurthwaite

So I've been going through Halo 4 on Legendary after taking some time off from it. I got through levels 1 and 2 without any issues. But then came time to play level 3: "Forerunner". After several failed attempts to load the level, a little message appears at the bottom of the screen saying I may be missing some downloadable content. Every other level loads just fine. Only Forerunner gives me problems. I downloaded the Spartan Ops Episodes 6-10 free DLC to see if that would work. No such luck. I tried re-installing disc 2. Nothing. Do I have to pay for DLC in order to carry on with the campaign? I was playing in co-op and when we reached the end of level 2 the game sent us back to the lobby, so I don't think restarting the campaign will fix the issue. My last resort would be to delete all of my saved data from my Xbox and start completely from scratch, but if anybody has any other suggestions they would be greatly appreciated.