yea it was that, its pretty complicated to understand. btw im in sec 3 and i havnt learned sin cos tan so i dont understand SHIT about that, i know what its for roughly but i can't understand it applied to anything yet, so i generally work around it.
i think your making this too complicated, you dont need the walls normal at all. i mean cmon its way simpler than your making, dont overthink things. why dont u just pull the object out the direction its moving into the wall, that would give exactly the same effect. just use some fastloops for your speed control and your done. why do you need normals at all? you'll naturally slip down the wall unless your walking straight into, it based on its shape.
i know what happened to you, it happens to me all the time lol, overthinking things makes you over look the simple solutions, and simple is almost ALWAYS better.
and dont limit yourself to boxes,unless your absolutley sure you want them, i hate games made using direct x that only use simple terrain elements or use pixelated graphics yet run at 80 fps, its a total contradiction of what your trying to achieve.