Norton is a whore - I'd use something else to be honest. I was a Norton user, then saw how Symantec Corp worked in the offices and compared to Norton, Norton was the bastard child no one wanted. It's horrible.
If your A/V is causing header referrers not to go through, you need think twice about using it.
You do NOT have to turn off your Firewall completely. That's bad practice, and to do that for ANY software, even WP is bad advice. You could be th eunlucky sucker who gets hit by a 2 year old script kiddy.
More often than not, these firewalls now have built in privacy features which are absolutely rubbish and do nothing to protect the computer as such. you need to turn off the privacy features, not your firewall's or edit your browsers to allow referrers if they're disabled. Do NOT turn off your firewall.
A/V is not such a big issue, as long as you have firewall you should be controlling what goes in and out of your system and if you're working on WP then there shouldn't be any problem turning it off. Still, it's probably a setting in the A/V software causing the problem and you have to add exclusion and exceptions.