JJ2 requires UDP port 10052 forwarded, as well as TCP port 10052 if you wish to host games.

First find out what the IP address of your JJ2 computer is (assuming Windows XP, as per your screenshot): Start-->Run, type "cmd" and press enter, then at the command prompt type "ipconfig" and press enter.

The IP address there is the IP address that you'll want to forward to. So in the Virtual Server section add two entries:

(Enabled)
Name: JJ2 UDP
Private IP: (IP address you determined above)
Protocol Type: UDP
Private Port: 10052
Public Port: 10052
Schedule: Whatever you want

(Enabled)
Name: JJ2 TCP
Private IP: (IP address you determined above)
Protocol Type: TCP
Private Port: 10052
Public Port: 10052
Schedule: Whatever you want

This question has been answered many times in the past, so next time try searching this forum before posting.