You haven't told us much.
How do you have it hooked up? It looks like it has video composite RCA connectors.
Do you have it hooked to just video? Or do you have a RG 59 cable to it, (Antenna coaxial cable)
Is alsa set up and working on your Linux box? Can you play an audio file? Do you have the neccesary codecs installed to play the audio stream of the video? .aac, mp3, etc.
If you hook the cable from your antenna or cable company to it, does it work?