I see, well there are a couple of things going on here. The window component you have set up IS successfully cutting a hole in the wall (yea!). But, all sides of the oval window component you have here are opaque planes including the back side which is the cutting plane, so it is cutting a hole in the target plane and replacing it with the closed back window plane. If you were to make the front and back of your window transparent, or erase them, you would see that your perimeter is indeed cutting a hole.
It sounds from your last post like maybe you are trying to cut a hole through your whole “wall” which is in fact made up of two planes about .01m apart. Components can only cut a hole in one plane, so if you place the component on the outside of your two planned wall you are only cutting a hole into the interior space of your wall, through the outside plane only. Push/Pull tool might be a better fit for what you want to do, but I’m guessing at what your goal is so I can’t be sure. Am I right that you want to make a window that has thickness?