We are using iPrint client 4.3.8 connecting to iPrint OES2/SLES10sp2
Zen is version 7.0.1

I can manually add iPrint printers using the ipp web interface and all is good.
However when I push the printers with a zen workstation policy the printers are installed but will not work. Trying to print to them locks the workstation.
the ippErrs.txt file shows

10/22/2008 - 4:49:45 PM
Module: spoolsv.exe
Trace Info: ippmain.c, line 14760, thread 00000F8C
Routine: IppInterpretUri - Bad URL (not HTTP, HTTPS, or IPP) - \\ipp://10.30.4.7\HS-MC156-CLR,DrvConvert
Error: HTTP - Bad URL supplied (not HTTP:, HTTPS:, or IPP:).

10/22/2008 - 4:49:45 PM
Module: spoolsv.exe
Trace Info: ippmain.c, line 10914, thread 00000F8C
Routine: GetPrinterInfoWithGoodStatus - Not our printer (\\ipp://10.30.4.7\HS-MC156-CLR,DrvConvert)
Error: The printer name is invalid.

Any ideas,
I suspect this to be a problem with the zen policy but I have no idea what is could be.