The reports I've seen from users appear to date back to 2011, so I'm surprised Bethesda hasn't fixed this already, especially when they fixed a separate bug from this quest before.
Can anyone help?
EDIT: Well, actually, I just realized I also own the game on PC and will do the save transfer procedure to enter in appropriate console commands that will allow me to proceed.
Still, Bethesda, you should really get this fixed. It can't be as much trouble for you as it is for those who experience it.