My canned answer to this question:
That
usually means you have the folder structure incorrect. Using "Flagg Park" as an example, you should have the following structure (there may be a few other files in there, but these are the ones that matter for the 3d park):
Code:
ballparks
models
Flagg_park
Flagg Park_Textures
Flagg Park.mtl
Flagg Park.obj
The .obj and .mtl files work hand-in-hand. The .obj file describes the actual 3D structure, and the .mtl file provides information about the textures. The textures have to be in the right location relative to the .mtl file. All of your texture files (the .jpg and .png files) should be in that "Flagg Park_Textures" folder.