That's because you didn't copy the materials correctly. Look in the console (~) to see what materials or textures are missing. Look for those in the ECA folder and add them to your map and material.cs files.
You have to make a new folder in levels, copy the GridMap files to it, then replace all "GridMap"s in the materials and other files to the name of your map, then copy the static objects from ECA to your terrain, plus the materials.cs files. Add to the materials.cs files if they are already there.