I don't know how it could have been incorrectly exported. As far as I can tell, I did everything to the letter, even with reading over the tutorial you quoted. :3
As I said, it looks completely perfect in the mapmaker tool when I load the map. It's in the game where everything goes wrong for some reason. :/
Could it be perhaps the folder placement? The folder is still located in Terrains... do I have to move it, make it a zip folder for it to work or something?
(As for the portal, I figure for that it's best to look up everything on that for now since I didn't completely look into that... I'm more worried on the fact that it's showing up flat in game. I can probably worry about the portal once that gets fixed.)