Add a printer under HP-UX 11.23

[Tim Plunkett]

I am attempting to replace the existing System V print queue on my HP-UX 11.23 server with CUPS.  I add a printer, for example, a Laserjet 4, with the CUPS-supplied driver 'HP LaserJet Series PCL 4/5, 1.3' and the URI 'ipp://bronze.psti.praxair.com/printers/islj4000'. When I print the test page, I get the following error: "Unsupported format 'application/postscript'!"
I have read about such errors, but am not sure if I even have the printer's URI defined correctly within CUPS.  How can I be sure my IPP is correct?  Any suggestions?
Printing works fine outside of CUPS.
Thanks in advance.