Close door asks for direction when standing on door and there's only one adjacent door open. It's not possible to choose "5" as direction.

Possible fixes:
- Do not count the door on the square you're standing on.
- Allow trying to close the door on your current spot and give the same message as you get when you're standing on a door and there are no adjacent doors open ("Move out of the door first.").

And one related thing that could be changed with this: [o]pen door also counts the door you're standing on (it says "The door is already open." when there are no adjacent doors or "The doors are already open." if there are).

Attached save (32-bit) has such case: load it and [c]lose door.