no audio out with insignia

I have a 32' insignia tube TV, it is no more then two years old. I recently bought a home theater systems (Phillips) and I am trying to connect the audio from the TV to the surround sound systems. I have tried all of the different cables (red and white also digital co axle) they are connected in the right place and i still get no sound out of the system. I have herd of this happening to other insignia's, does anyone have a fix?