lex wrote: But there's an empty space on top of the ad banner and the mod's developer said it's because of the ProNight theme. So can any of you guys help me here?
The theme would make no difference to that, not sure why he said that? It is based on prosilver so if you get an error in ProNight, it would show the same in prosilver default phpBB style.
What you are asking is directly related to css in that mod.