ConfusedBW, do you have XP's software firewall activated? That would block port 5517.
Start>Settings>ControlPanel>NetworkConnections>"Your connection">Properties>Advanced
Uncheck the firewall box, or if you want to use it, click on Settings, and add an entry for TCP port 5517.
My Queue is open on port 80 as well, but I haven't found that to help with company firewalls.