My thoughts are the problem lies with your set up; the routers ... at least two are port forwardable. And one of those is reknown as a problematic router model series. The latter being the Linksys which can be very unreliable when run in UPnP mode.

You could try Port forwarding. Very first thing to do here is set up a static ip: set up a static IP on vista

Find your Linksys model here PortForward.com - Free Help Setting up Your Router or Firewall

As for your software firewall, choose one or the other, Vista or Norton firewall to run (these two are known to clash); configure the one chosen to allow LW full access: Setting up an exception for LimeWire in your software firewall (click in link)

Also, see If LW Will Not Connect (click on the blue link). Disabling performance options might help in your case. Also deleting the gnutella.net file. You may wish to try this first before the very first suggestion.