In order for Novell's NDPS Gateway to be able to talk to the printer, it
must be able to ping the printer. So, if you have a firewall between the
server and the printer, you must make sure that your firewall is
configured to not just let the LPT protocol through, but it must also
allow the ICMP protocol between the server and the printer.

Note that the communication failure messages can never be due to your NDPS
design or the location of the NDPS objects in your tree. It's only a
matter of network traffic between the server running the NDPS Manager and
the printer.

Marcel Cox
Novell Support Connection SysOp