Kyle,
On my receiver, I can select analog or digital as the input source for certain components, TV being one of them. Perhaps you need to select "TV" and then also select either "digital" or "auto" (meaning it will pick whichever it can) on another selection button. Sorry, I don't have time to read your manual at the moment, but I'll do it later if that doesn't work for you.
In regards to getting DD and DTS to play through the DVD player, some DVD players require you to go into their setup menu and select bitstream (instead of PCM) as the output for DD and/or DTS. If you don't do this, then you'll get stereo sound instead of DD or DTS. My first Toshiba DVD player was that way, and my current Panasonic DVD player had to be set up to output DTS. Might want to give that a try.
Good luck, and let us know if that doesn't work for you. Thanks.