Hi guys! The problem with the RPGMaker is that it only allows 2 layers over the pavement, that's why, for example, you can't place a pile of paper on the same tiles of a table with a lamp on it (max 2 objects on the same tile)
For what concerns the walls, you need to set them as the "A4 (Walls)" in your tileset!
Here's an example on how it should work
