I find with dlinks...you have to be sure to enable the rule....is there a check beside your rule

Also if you are running windows xp..you will have to enable the ports in the windows firewall

Dlinks usually have an application tab where you can use pre configured settings......

another thing you may try is give your machines static addresses....by turning off the dhcp on the router and manually configuring ip addresses on your machines behind the router......

Just things to try...

Do you have any anti malware software that maybe blocking connections to your computer???

MLF