are you connected as an UltraPeer ?

Have you applied the EviD Patch ?

http://www.gnutellaforums.com/showthread.php?t=57438

Are you sure that you are allowing enough bandwidth for messages (Upload speed should not be set higher than 80% of Max (Google for a speed test if unsure of real speed. It's always lower than the advertised speed)

Also your ISP can have started trafficshaping P2P bandwidth (Gnutella Network which Limewire connects to among others)