printing postscript over network

I am currently in the process of configuring some pc's to replace some
old WYSE terminals. I need to organise a single key press which will
print a screenshot of the screen to a network printer.

To print the screenshot I use

xwd -display localhost:0 -root | xwdtopnm | pnmtops | lpr

This will print if done from the print server, but not over the
network.

Cups error log on the server shows that the job is being sent to the
printer, however nothing gets printed.
/var/log/cups/error_log

AcceptClient() 7 from 192.x.x.x:631.
ReadClient() 7 POST /printers/HPLaserJet1100 HTTP/1.1
ProcessIPPRequest: 7 status_code=1
ReadClient() 7 POST /printers/HPLaserJet1100 HTTP/1.1
print_job: request file type is application/postscript.
CancelJob: id = 1918
check_quotas: requesting-user-name = 'remroot'
print_job: requesting-user-name = 'remroot'
Adding start banner page "none" to job 2416.
Adding end banner page "none" to job 2416.
Job 2416 queued on 'HPLaserJet1100' by 'remroot'.
Job 2416 hold_until = 0
StartJob(2416, 0x8307890)

[Job 2416] Printer: HPLaserJet1100
[Job 2416] PPD file: /etc/cups/ppd/HPLaserJet1100.ppd
[Job 2416] Printer model: HP LaserJet 1100 Foomatic/hpijs
(recommended)

blah blah blah(searching for header options)

[Job 2416] Renderer process finished
[Job 2416]
[Job 2416] Closing foomatic-rip.
UpdateJob: job 2416, file 0 is complete.
CancelJob: id = 2416
StopJob: id = 2416, force = 0
StopJob: printer state is 3

The network printing works fine if
a) text file is sent
b) ksnapshot or other program sends a postscript file

It appears only to be a problem with postscript sent over the network
from a command line/shell script.

Can anyone see what I am missing, or is there some bug/feature I am
unaware of.

Lost and confused

Andrew