ARRRRG

I'm on the 3rd test of the Nerevene, and I can't get into Koghruhn. When I try ANY of the doors (including the outlying huts, and the entrance on the roof) The game tells me that the doors are blocked from the inside, and that I need to find another way in. I get this message when I try to enter ANY Daedric fortress (Falysamaryon, Valanvaryon, etc.) Daedric shrines and Dwemer ruins are fine, only Daedric fortesses have a problem. I've been inside Daedric fortresses before this misson, they just suddenly stopped letting me in. If it matters, I have Bloodmoon, and the 1.6.18 patch. I'm also running TON of mods, but it's mostly mundane stuff (the cloak mod, the Isengard mod, etc) so I can't see any of those causing trouble. I'll try removing some mods, but any help would be greatly appreciated.