command line render only gives me a cube

Hi guys,
I’m trying to render a movie from the command line to decrease the render time (a complex scene). However, when I render a single frame or the whole movie, I only get a .png for each frame and it’s always the default scene (grey cube with grey background) even though I have a complex model in there.

I’m following the directions given on the blender wiki for 2.5x, in the render>rendering from the command line section.