Joe's guide to testing network connections:

1. Figure out which port you're trying to connect to.
2. Make sure the port's open (netstat in unix, I have no idea in windows)
3. Connect to the port from the target machine on loopback
4. Connect to the port, from the target machine, on the external ip
5. Connect to the port from a remote machine, using the target machine's IP address
6. Connect to the port from a remote machine, using the FQDN.
7. Attempt to use whatever automated scripts, local to the target machine
8. Attempt to use whatever automated script from the remote machine.

Based on how far you get before failing, you can get some idea what might be wrong --

1. (nothing should fail at this point)
2. The daemon's not running, or whatever needs to be listening
3. ditto, or it's not listening on loopback (not all do)
4. It's not listening on the external IP
5. it's firewalled off, or tcp wrapped, etc.
6. DNS isn't set up correctly on the remote machine, or the FQDN isn't in DNS
7. The script may be flawed, or misconfigured.
8. Ditto, but on a different machine.

Some protocols are trickier to pin down, especially if they result in the remote server connecting back to client (eg, FTP in active mode). I have no idea how TieRegistry works, so it may not have these sorts of issues.