So, you were trying to listen through tv speakers? No need to use receiver if you're going to listen through tv speakers. Just run component cables straight to tv for video. Since tv has no digital inputs for audio, except HDMI, you'll just need to use the red & white analog cables to tv, for...
You aren't trying to play the sound through tv's speakers? If the receiver shows "Dolby D" in it's display window, when a dvd is playing, chances are it's a 5.1 surround signal it's receiving. Using optical for audio, you may have to assign the input you use, since the receiver doesn't...