Often if you update Norton or LW you need to re-add LW to the safe zone of the firewall. See Reconfiguring Norton Firewall. Also make sure your XP or other firewalls are disabled. Norton & XP firewalls tend to clash badly & result in less security, not more.

Another option is to delete your LW Preferences folder whilst LW is closed; instructions here: Point #2 & 3 in Fixes for Limewire (sample image included at bottom of page.)