Hello, I am pretty good with computers and stuff but when it comes to all the connection and firewall stuff I get confused. So please bare with my ignorance

I have had Limewire on my computer for years but have not been able to figure out how to connect it for some time now and I'm will to spend the time needed to figure it out.
I tried using the self help FAQ's but didn't get any results. I tried turning off the XP firewall and that didn't help. I think its a firewall thats messing with my connection.
I get a message screen that says Error:
"Your machine does not appear to have an actice internet connection or a firewall is blocking Limewire from accessing the internet. Limewire will automatically keep trying to connect you to the network unless you select "Disconnect" from the File menu."
1. OS version? Windows XP
2. What firewalls you have?
3. How much ram? 640 RAM
4. Hard Disk space available? 6.5 GB
5. Connection type? Cable "Comcast" San Francisco area
6. Modem & router brand name & model numbers? Scientific Atlantic (DPX2100)
7. Where are you trying to connect from? Home
8. What version of LimeWire (LW) & Java do you have? LW 4.12.11 Java 1.5.0_06
9. Who is your ISP provider (Internet Service Provider)? Comcast
10. Do this simple test for us. Using your browser go here: "your test worked"
11. Are you sharing the connection with other computers or p2p sharing programs? I have kazaa lite folder on my HDD but not installed
12. Is this a your 1st try at LW or is this a new problem with an experienced user....ongoing issue, LW has worked in past though but on another ISP
13. Do you see a brick wall in front of the blue world icon at the bottom of LW's interface? yes
14.
For those using a modem/router, how is your modem/router set up...are you port forwarding or is UPnP enabled? I dont know?
15. What security programs are you using (antivirus etc)? I have an expired norton and AVG and XP security
16. What country are you living in? USA
THANKS For the help