Are those computers all connected in a sorta network? And if, did you install LW while you were logged in as Administrator?
Turning of the Firewall isn't advisable. Better to configure it properly, i.e adding LW to the Exception List and opening the Listening port as both TCP and UDP.
Take a look here:
http://www.gnutellaforums.com/showthread.php?t=51361
Cheers
FOTH