Direct Connect is fussy. If there's any firewall detected then it definitely won't work. Don't disable your firewall. Instead configure it: (advisable not to have 2 active firewalls b/c they can interfere with each other); Firewall configuration instructions (click on link)

2. Most wireless devices have internal NAT firewalls. Forward a port on your belkin: go here http://www.portforward.com/routers.htm. I don't think Belkin supports UPnP. I searched their support site & came up zilch. Also history on the forums shows Belkin users are much better off port forwarding for reliability.

BTW if you're firewalled, then you won't see your external ip at the top of the direct connect search box. How to Direct Connect, Browse & Chat

You both need to have available upload & download bandwidth & slots to be able to direct connect. Another good way of connecting together is using a magnet link. Then when you connect, browse them. And vice versa thru the upload window. But chat should be enabled for browsing. How to use Magnet Links & Direct Connect