LexMark X738 errors on scan

[leericmarvin]

FHC has a Lexmark X738 which errors
"Connection failure: Unable to make a TCP
connection to the server" when it scans to a
computer.
I have one computer which works OK, but 5
others which produce the above error. I have
GIMP setup the same on all 6 computers. I
can't figure out what is diffrent on the 5
computers to not work.
From the GIMP end, it sits in "Receiving..." for several minutes, finally "crashes" out and then printer spits out error message.
I have ensured the firewall is off. Have compared TCP settings.
Also, the computer which works was the first one setup to communicate with Printer. Could subsequencly installed computers require some kind of manual "authorization" made on the printer?