Aaahhh, sorry about asking for your system details again...I copied/pasted part of my reply & forgot to remove the system details bit
Did you remove any other Java versions installed on your computer, so that the only version you have is 1.6.0_03?
If you're sure that you did the replacing of gnutella.net properly (with LW completely closed), try changing ports. In LW tools > options > advanced > firewall config, change LW's listening port to 65000 (or you can also try other ports in the range of 49152 - 65535). Change the port in the 'manual port forward' box to that same number > apply > ok. You'll need to go back into your router's config pages & change your forwarded port to the new number as well.