I'm wondering Mkreku, if you were running the game with mods installed? And if you are, have you tried troubleshooting them?
Well, I was using a few different mods, but when I bought the DLC I un-clicked them all in the launcher. I didn't know if they would be compatible. Hmm, maybe I should do a clean install? Or could the mods be affecting the game even when they're not being used (except for one small interface mod, think it was called BetterUI)?
The game and mods are suppose to follow a certain order. One way to make sure this happens is to use FOMM, Fallout Mod Manager. Order of preference is Fallout3.esm, DLC (Which I would set in the order they were released), and mods. Some mods should be set up ahead of other mods. Just read the installation text to see if mod x needs to be ahead of another. I thought the Anchorage DLC broke my game because after I did that, I couldn't go inside any buildings in any of the DC area. It just so happens I didn't have the proper install order. I had mods that were ahead of the Anchorage DLC.