log on to your router: 10.0.0.2, enter details. Click on advanced on the top.
Hover your mouse over "applications" on the left, you will see a list come up. see if the light next to "UpnP" is green, if its not, click on UPnP and then tick the enable option. Then below that select which WAN connection you are currently using. Choose LAN Group 1 in the following option. Click apply and then click Save Settings on the top left of the screen. I sometimes forget to do that.
Now that that is sorted out, open up limewire. Click on tools on the top, then options. Then on the bottom op the box that opened, click on Advanced, it will open up a list underneath it, Click on firewall config and then make sure option "Use UPnP (Recommended)" is selected. And then just click apply and then OK. Restart Limewire. and maybe your router too just to be on the safe side.