tightvnc, belkin router, port 4900 open, still cant connect

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http://serverfault.com – My computer on a private LAN, which connects to a router, which is connected to the internet. Their computer is behind a belkin wireless router. I have turned the firewall and AV off for the computer that I am trying to connect to. I have also gone into the router settings and opened port 5900. (to clarify : the setting seems to be a mapping of her LAN IP to the port number. The checkmark for 'enabled' is checked, and it is her correct LAN IP address, and 5900 is the port) I installed TightVNC server on their windows 7 computer, and it is running as a service. I am using ubuntus Remmina Remo (HowTos)