This story just doesn't seem to die. The LockMart engineers made an error on one of the trajectory parameters they sent to JPL. From memory, the parameter had to do with the amount of delta-v imparted when the thrusters fired to unload the reaction control wheels. JPL's error was in not catching the LockMart mistake. Also, I don't know why JPL didn't catch the fact that the trajectory was off by roughly 90 kilometers as MCO begin the orbital insertion burn. They're normally a lot more precise than that. I've heard that budget pressures meant that less experienced orbital analysts were assigned to the mission. Still, the original error was LockMart's, not JPL's. The accident report is available here.