Sequencer render problem

Hi,
I have been trying to render this sequence as a background for friend’s videos, and I’m using 4 duplicates of a scene in order to be able to change the cameras.
The first time I rendered overnight, it got the first 4000 frames out without a single problem, but now that I want to finish it, I can’t because all it renders is a black screen.
So I looked inside the scene themselves, and rendering a still from there works fine. Then I render a still from the sequence, and it works too. But when I hit CTRL+F12 and continue my animation, I get black screens.

This is the first time I get to play with the VSE, maybe I’m doing something wrong.

Here is the blend file: (don’t worry about the stamps being activated)
http://www.pasteall.org/blend/31119

  1. I found no problem rendering a sequence of frames as an animation using ctrl f12.
  2. I seem to be missing a node group in the compositor tree?
  3. You don’t have to duplicate scenes, you can alter the VSE scene strip to use another camera. Just put a bunch of cameras in the one scene, then switch in the VSE.