Sorry to sound offensive, but, advising somebody to disable their Firewall is NOT a good thing!
Firewall on - Your invisible to most hackers
Firewall off - You may as well invite them in!
You can never take internet security for granted.
I've had my machine trashed whilst playing on a "Non Firewall" server! :'(
Stupid me!
I'd hate to see any of the guys here fall victim as I did.
I have a Hardware Router and Firewall, Hackers still have a good go from time to time! ::)
There is a warning about leaving yourself vulnerable if you switch your firewall off, but sometimes in order to eliminate that as the problem you need to switch it off. If you are behind a router then a firewall is only really necessary to prevent unauthorised outgoing traffic. NAT firewalls are extremely good at keeping out unwanted casual visitors but not so good at keeping in escapees. Any serious hacker will get through most publically available firewalls. However serious hackers are more interested in getting through the firewalls of large institutions and companys.
Switch your firewall off at your own risk!!! but if you want to eliminate a possible problem that's what you need to do.