I'd hate to be a bother, but I'm not sure how to get the dirt to show up on Map Maker's list. I know I need to do something with Object Maker, but I've never used that before. XD A pile of dirt can actually be more useful than one might think.
Here I will give you some step-by-step directions.
1. Save all files into your My_Objects folder.
2. Go on FH and open up Object maker.
3. Go to the Mesh tab
4. Where it says Mesh type in: ground_pallisade.mesh
5. Where it says material type in: Dirt
6. Check off Own Collison
7. Save it in one of your object groups!