I have already placed this double-door(from World Adventures) on a diagonal wall as follows:


It worked great on the 1st floor, but when I started with the 2nd floor I just couldn't make it work again:


I already tried moveobjects on, it just says "cannot do that". And it's not about the stairs being too close, I tried moving the entire diagonal wall backwards and even making the room behind it empty(not even walls, just floor); still didn't work. The only difference I can think of is that when I made the 1st floor I hadn't put on the roof yet, but for the 2nd floor I have already placed the roof.

Can anyone help?

you should be able to place it with moveobjects on.
Then turn moveobjects off, select the door and hit esc to ''unerror'' it

Try using the CFE cheat just to put the door there.
I had the same problem once with diagonal walls and doors, for some reason the only way the door would snap in place was by using that cheat.

Worked like a charm, thanks a lot!