Microsoft Office Outlook is synchronzing folders, what does this mean?

Whenever my Norton Internet Security 2007’s firewall is on I cannot send or receive my email. I turn off ther firewall and it works fine. This never used to happen until yesterday. I have read many of the posts and tried several things but with no success. I went to Nortons site and installed the latest fix and downloaded all the most current updates and still no email unless I turn off the fireall. I am running on an HP Media Center with Windows XP Media Center SP2. Outlook 2003 SP2. Any help would be greatly appreciated, thanks.