OK, let's start from the top. The computers, what are their IP addresses? If they're not in 172.16.x.x-172.31.x.x, 192.168.x.x, or 10.x.x.x, don't put them in; otherwise it's safe to post it.

If you look at the Denon network info, does it match the same pattern as the computers?

If so, go to a computer and ping the Denon's IP. If that works, it's on your network, it just can't find the internet, which probably points to either a gateway/routing problem or a DNS problem.

I am the Doctor, and THIS... is my SPOON!