Your zone name may be your problem.
The Chooser supports a maximum of 31 characters for a device or zone name,
and your name is 34 characters. When the additional device names are
appended to the data packet to make a complete address string, the string
gets truncated by a lower-level AppleTalk routine. At that point, the name
string doesn't match the actual address, and a search for that device
fails.
Shorten the zone name to something under 30 characters. Also check device
names to verify that they, too, are under 30 characters.