I presume you only have one firewall right?

Well if it was working fine before but not now, then perhaps deleting your LW prefs will do the trick. Try deleting your LW Preferences folder whilst LW is closed; instructions here: Point #2 & 3 in Fixes for Limewire (sample image included at bottom of page.)

BTW as an experiment try downloading a magnet link from here & tell us what happens in regards to connection status & speeds: http://www.magnetmix.com/video.shtml