Yes I have had same problem - Answer was in the latest edition of PC Advisor!
Click Personal Firewall
Click on Configure then select Custom Level
Deselect Enable Access Control Alerts
Suggested that you also deselect
Alert when unused ports are accessed
Did this about an hour ago and have had peace for the first time since installing Norton!
(I assumed that you needed to select this option through the Intrusion Detection feature, but that did nothing at all to help)
Hope it works for you too!