I remoted into your server and found and fixed the problem.
The "Device Address" field should contain the unique serial number identifier of the AppleTV. This is extracted during the discovery phase.
On your server the "Device Address" field was set to the IP address of the AppleTV. This was an invalid value for the GetApps command and generated the response in the log saying that no AppleTV could be found.
I edited the entry and changed the Device Address field to its correct guid serial number and you now have apps showing up in the list.
