Maybe you are missing the gstreamer library. Does this command work for you?
sudo pacman -S gstreamer gst-plugins-base gst-plugins-good gst-plugins-bad gst-plugins-ugly gst-libav
Might be that you require to add more housing so younger immigrants appear in the city. You can check the median age of citizens in the "Stats" menu. Please note that is also necessary that the homes of workers is connected via road to the factory. You can probably also increase the taxes to recover funds.
I'm trying to think how the interface can aid a bit better in solving this kinds of problems. Expect an update soon :)
Oh also, I just published a small text that can guide you into how the simulation works. http://microlandia.tubatuba.net/simulation_details Please feel free to let me know if you still don't manage to reach economic balance, so I can perhaps investigate if there's something wrong with factories.