Every time I play Stonekeep, I run into the problem of the Shadow Skulls just east of the entrance not appearing and being unable to attack. Is there any way to get them to do so? They're in the area just south of the red half of the yin-yang symbol. The problem persists, whether in DosBox or in the real DOS. Shooting a Black Slayer Arrow down the corridor from a corner destroys them, because I see the arrow fell on the floor before it could hit a wall.