Instead of disabling your firewall, it's better to configure it properly. If you have a Norton firewall then disable XP's & configure Norton.
See of you find any help in the sticky below
Connection problems? Check here first!

If you're stuck, post back with your details
System details

Hi, I already tried configuring Norton as suggested by permitting LimeWire but it was still showing as behind a firewall.

1. OS version? (eg: Windows 98) Windows XP
2. What firewalls you have? Norton, XP, BT HomeHub
3. How much ram? 512MB
4. Hard Disk space available? 20GB
5. Connection type? (eg: dialup, broadband, cable, etc.) Broadband
6. Modem & router brand name & model numbers? BT HomeHub
7. Where are you trying to connect from (home, school, work, etc.)? Home
8. What version of LimeWire (LW) & Java do you have? (Go to LW's menu Help>About LW...) Will show both LW & Java version. LimeWire 4.12.6 Java 1.5 Update 9
9. Who is your ISP provider (Internet Service Provider)? BT Yahoo Broadband
10. Do this simple test for us. Using your browser go here: http://www3.limewire.com:6346/ The page should say 'Your test worked!'. What happens when you go there? Your test worked
11. Are you sharing the connection with other computers or p2p sharing programs? If yes, please give details of set up. No
12. Is this a your 1st try at LW or is this a new problem with an experienced user. New problem with experienced user
13. Do you see a brick wall in front of the blue world icon at the bottom of LW's interface? Yes