i'm doing the dark brotherhood quests, and i get to the point where i just killed the man with a bow, and lucien is supposed to come out and tell me i did everything wrong, but instead he just stops infront of me and my character (who is frozen for the scene) stays frozen. what is going on?

I would say that some mod messes it up - try and turn off all the mods except Oblivion and do the mission. Good luck!