Forum:Knoxx Vault wont open

I beat general knoxx, finished the quest, and turned it in. I want to go fight him more to go through the vault again, but the door won't open once I beat him. After I beat him and get to the door, the code is already entered correctly and the door with he green light is open. I walk inside and the vault gate doesntt lift up like normal. Also when I enter to fight general knoxx, It doesntt do the cut scene of him entering out of the floor. I just go straight on to fighting him. Does anyone know how I can fix this?