After Grace goes down the dumbwaiter and gets caught, you direct Carnby to grab the key and unlock the irons. The Zombie holding Grace lets her go and fights you. The first time I did this, I was able to kill him and move around the room, but after that I was unable to move from where I got up. The walking animation is shown and I can spin around, but that's all. I can't move from the spot where I stand up. Multiple reloads of 2 different files can't correct this problem. Anyone else have this problem?

I haven't found a cause to the problem, but I may have found a patch. It seems that running while stuck jars the character out of the problem area. I hope this helps others in the future.