Try these things one by one to see if they have any effect:

(a) disable Little Snitch. I've heard of it causing problems before.

(b) Is OSX firewall on or off? If using another firewall then disable OSX's firewall (you will find it in System prefs, Network -> Firewall tab). Make sure you allowed LW, Gnutella & the port range you are using thru on the firewall rules for the NetBarrier X4r.

(c) Go to LW's Preferences > Advanced > Firewalls, & change the port to another. Good ones to try are between 49152 - 65535, such as port 64049.