Whenever I open the webgl_loader_fbx.html, I can only see the empty scene. File paths are OK, and I did not add or delete a single line of code. I don't think I am doing anything wrong.
Here's what I see:

What might be the problem?
See how to run things locally — for examples that use 3D models or textures, you'll need to either use a local server or change settings in your browser.
If you're still having trouble, please use the forum (http://discourse.threejs.org/) for help. :)