I have Fallout 3 GOTY, and installed all my DLCs before I ever started the game. I've gotten a confirmation message, saying that Broken Steel is loaded, and my character is level 22. however, upon finishing the Take It Back! Quest, by entering the purifier and starting it, I get an ending movie and I'm taken back to the Main Menu. I disabled all my mods; same result. As an added bonus, I can't convince any of my followers to enter the purifier. Well, i can, but Sarah Lyons always enters the airlock and tells me to shut the door. Apparently she thinks she's a Super Mutant. Or a ghoul. Or a robot.