Have you tried port forwarding for the Netgear, or are you using UPnP? In LW go tools > options > advanced > firewall. Tick the box to use UPnP > apply > ok.
Now log into your router by typing 192.168.0.1 into the address bar of your browser. Default username is admin, password is password. Have a look in the sidebar for a UPnP option (below Static Routes in the Advanced section). Click on UPnP & make sure that it's enabled (ticked). If you have to tick the box, click Apply afterwards.

If using UPnP is no good, try port forwarding. I can't find instructions for v4 but these should be the same: Port Forwarding for the Netgear WGT624v3

Choose a high listening port for LW. Try 65000, or any ports in the range of 49152 - 65535. When you change LW's listening port number, remember to click Apply to save the change.
LW's listening port, port in the 'manual port forward' box & port forwarded within the router setup all have to be the same number