Have you tried reconfiguring your Norton firewall? See LOTR's post below, it has links
http://www.gnutellaforums.com/showpo...97&postcount=2

A few people have found that they've had to start from scratch with Norton, after updating their LW.

If that's no help, post back with your details (forgive the repeat questions!)

OS(Win XP etc)
LW & Java version (help > about LW & you'll see)
Firewall you're using
Modem/router brand & model
ISP
Connection type (DSL etc)
Where you connect from (home, school, student accommodation etc)
Are you sharing a connection with other computers
Is this your first try with LW

How did you have your router set up for the old version of LW (port forwarded, UPnP enabled or neither)?