All went well last night and again this morning, I stopped for lunch and when I came back, there it was again - "The Wall" has returned.
It still appears even when I disable the firewall in system preferences.

I have screen-shots of all the prefs windows but I don't know how to attach them to this message, so I'll try to describe them to you.

In system prefs - personal file sharing is ON
Firewall is enabled for personal file sharing, iTunes and Gnutella/LimeWire
iTunes - TCP port Number is 3689
iTunes - UDP port Number is blank
Gnutella/LimeWire - TCP port Number is 64049
Gnutella/LimeWire - UDP port Number is 64049
Advanced options - none are selected
Internet sharing is OFF (You cannot start internet sharing because you have not selected a port over which to share your connection)
Internet settings show Voyager 105
Built-in ethernet and Built-in Firdewire ane NOT selected

In FW prefs - Listening port is 64049
Router configuration - UPnP is selected
Manual port forward is NOT selected but is set to 64049 also

These settings are locked and have worked succesfully since your last instructions.