1. Delete the LW prefs folder Deleting LW Preferences folder in OSX

2. Go to LW's prefs (keyboard shortcut: Command (apple key) & Comma ⌘ , & select Connections & disable connect on start up.

3. In LW, click on File > disconnect. Wait 5 minutes, then File > connect.

4. If still problems; REPLACE gnutella.net FILE, but first Close LW.

The link below will take you to a file hosting site where you can download a file named gnutella.net. zSHARE - gnutella.net
If that link doesn't work, try this other one. gnutella.net