not sure if this well help...I had a similar problem, Limewire was working fine until a few weeks ago, then all of sudden I was getting connection problems....on my system (I'm running XP with a firewall) it looked like running limewire was causing my entire internet connection to become unstable (Limewire was not connecting properly, I noticed msn would periodically disconnect, I had trouble loading webpages that I knew were fine etc..)

I tried all of the fixes suggested here and nothing worked (very frustrating) and then buried deep in one of these threads I read a suggestion to set the "listen on port" setting to "80"
(tools -> options -> advanced -> firewall config) instead of the default 6346

...seemed to work, I've been back up and running now for two days with no problems....maybe just a coincidence???

(by the way, I'm admitedly not altogether computer savy...can someone explain what this setting does, and if I should be concerned about changing it...ie. potential conflicts with other programs? security risks? thanks..)