ah.. Windows xp... M$ sucks. XP SP2 limits the concurrent connections to 10 on one port (on gnutella it is by default 6346) over a second. More connections attemps are blocked. SP2 sucks for P2P programs. There are four solutions:
1)download LW 4.1 beta @
http://www.limewire.com/english/content/beta.shtml which attemps less simultaneous connections.
2) search on the web for the patch that let more simultaneous connections (patch not from M$)
http://www.lvllord.de/4226fix/4226fix.htm isn't working now but this site contained the patch.
3) uninstall SP2
4) switch to Linux or Mac os x
I'm so happy to be a mac user!