Throw "Prefab "+unk.getPrefabType()+" was not compiled";

I looked at the sample in the heaps. There is only FxView in the example. When I load the .l3d file in the same way, I get this error -> " Throw Error: " val: “Prefab model was not compiled” "! ".
I want to know how to load and display level3D file?
How should it be compiled?