Definitely disable the Windows firewall for all of these initial tests. If you can get it working with the firewall disabled, then later we can get it re-enabled with the appropriate pinholes.

PC-Cillin should not interfere with the Audio Receiver Manager software unless it also contains a firewall-like feature of blocking applications from talking on the network. Either way, though, temporarily disable it to see if that fixes the problem.

Is there anything else that you can think of that maybe you installed on the PC that might interfere? I'm thinking in the areas of:
- Blocking application access to the network
- Blocking incoming network traffic
- Modifying the network traffic, such as altering packet size
- Web server host applications on the PC
- Proxy applications on the PC
- VPN software
- Anything that messes with Winsock or puts a shim into the network drivers, like old versions of AOL did