It appears that Norton Firewall closes the connection when it finds specific keywords in it's TCP/IP stream. Typing startkeylogger in a crowded IRC channel will probably cause some disconnects :)
norton, meh
I can't say I ever recommend anything Norton or Symantec, especially Norton.
For firewalls I recommend Kerio for the clueful and ZoneAlarm for the clueless (really Kerio any more).
For anti-virus it's AVG and Antivir although I've been meaning to revisit clamav/clamwin.
Norton just seems to get into everything and not allow you to extricate it.
