I suspect that your downloaded window came into ArchiCAD as an object not as a window element. This might be able to be changed with some GDL scripting, but I can say for certain.
You could place it with the object tool, but it won't cut the walls properly nor would it schedule properly.
Erich
AC 19 6006 & AC 20
Mac OS 10.11.5
15" Retina MacBook Pro 2.6
27" iMac Retina 5K