I'm trying to fallow this tutorial, but I am only rendering black images (or videos).
I only have downloaded the file and tried to render with Blender 2.74 on MacOSX and Blender 2.76 on Windows 7 (and also old versions of blender). I already checked lights, camera, layers and scene. I also tried both Cycles and Blender Render.
I cannot find the problem!