You may want to make sure that you don't have the audio cables connected into the TV's output. Other than that, I'd need to know the complete product code in order to guess what might be going on.
I have just set up my new samsung tv and want to connect my lg dvd player for both watching dvd's and using as a sound system. I had the dvd player rigged up to my old sony bravia via the red and white audio output and had no problems at all using the dvd in aux mode. I have set the system up in exactly the same way with the samsung but for some reason i have been unable to get any sound from the speakers. I have been through all the settings i can find but to no avail. Can anyone give me any idea where i'm going wrong.