I'm working frantically to try to catch up on an enforced break from blender, so bear with me, Shaddownigh, but while it's a bit quiet around here I wonder if I might be able to help you work around your problem.
I've been diving head first into the nodes side of things and I think I love it
, but I have had similar results to yours with the black screen thing. I wish I'd written down what I did, but just checking and re-checking EVERYTHING for me did get my render a bit better. My silliest problem has been caused by not rendering each layer [via the layers panel under the Render button, right hand side].
I haven't got as far as applying sound yet.
I'm probably WAY behind you with experience, but maybe it's a "did you check the fuse" situation?
I can't wait for the Big Guys to get back from their holidays, or wherever they are, but until they do we should still try to get things done by ourselves