I work in logistics for the DoD. I have three friends stationed out there, one of which who just was moved from the tent city a few hundreds yards shy of where that 747 crashed at. The civilian contractors are supposed to take the load plans we give them and assemble the load ACCORDING TO THE GIVEN LOAD PLAN. More times than some, they will tell us to fuck off and they will load the aircraft as they feel. You can get away with that on the 74's because the allowable cabin load is incredibly high.
Now for a possible reason of crash...one of the first avation reports stated that the crew(during take off) mentioned something about load/cargo shift. And there were several armored vehicles on board that weigh up to 30,000lbs. If those vehicles shifted to the aft of the plane during takeoff(and those guys abuse the hell out of birds on takeoffs) then that would explain the aircraft getting stuck at nearly an 80deg angle, leaving it without enough thrust to recover.