Your file name has some freaky characters that the game can't handle. After renaming it, I could test it.
An easy fix is putting your thok barrier with the two heights at above the floor height, then giving the floor a texture. Afterwards, texture apropriately.
After that, this is your average, uninspired, flat plane. At least your rings were together. Please, try something with a goal in mind. Other wise it always comes out like this, with those specific textures. Always.