So you tried a combination of the other fixes in the above link?
Vista firewall should not be turned off, simply configured to allow LW; User Cant Connect - LimeWire

The fix is not always the same for everyone. Sometimes there's one of many things that might be problematic or a combination of them. Disabling all performance options, replacing gnutella.net file. Or possibly deleting LW prefs, if that does not work, replace gnutella.net file & disable performance options again. Getting rid of old incompletes will most likely help too, stop them 'flooding' your router connection whilst LW is attempting to connect.

So did you set up a static ip & forward a port in your Motorola SBG900? Good ports to try are between ports 49152 - 65535. The same port would need to be added to LW's advanced -> Firewall setting with it set to port forward.

You could try Phex & see if it connects. http://www.gnutellaforums.com/phex-c...-released.html. It's a great program, just not as intuitive to use for new users.