Try deleting your LW Preferences folder whilst LW is closed; instructions here: Point #3 in Fixes for Limewire (sample image included at bottom of page.) or if using Vista see http://www.gnutellaforums.com/genera...der-vista.html

Then after opening LW give it time to connect. If no connection, try changing the connection port (to one between 49152 - 65535) listed here: Tools -> Options -> Advanced -> Firewalls. OR if using LW 5, change these settings under SuperReallyAdvanced section.
Need to make sure both LW's are not using the same connection or listening ports.