I don't use Firefox so I can't help you out much with that part, but I do have Norton 360 and I hate it. I liked Norton so much better when you could have the firewall separate from the antivirus, not so much of this integrated stuff.

Is it giving you any messages when you're trying to access the pages? Sometimes it will give you a box to allow or block certain web pages, if you just click 'allow always' it should stay in the program and not keep bugging you.