Distributing the internet either by wireless or by Ethernet cable

Sounds to me that the router is not recieving the signal from the Modem. Some Modems require you use a 'cross-over cable' to plug in a router like that (from modem to WAN on D-link). Make sure the IP address of the D-Link is on the same subnet as the Modem, i.e. the cable modem is preset with an ip address scheme (proabably 192.168.0.1 or something) and your router should have the same 192.168.0.x address depending on what the modem is).

Another thing you can try would be to "bridge" the modem to the router.

Look here, http://www.computing.net/answers/networking/dsl-modemrouter-in-bridge-mode/28151.html

Also if you need troubleshooting walkthrough Im available http://www.hoosierpcrepair.com