I'm stuck in chapter one with the escort yerske mission. When I go into the sewer (either before or during the mission) all the doors are locked and it gives me the circle with lock and red background so I can't even attempt to pick.

I've looked through my log and except for going to the 4th tomb (Qaa) I have no other open quests.

Anyone got a clue of what might be happening? I'd hate to have to uninstall because I can't go any further.