[Printing-architecture] Correcting 'filter failed' error

If this is not the proper mail list for my problem, please point me to the
appropriate one.

I'm running Slackware64-14.2 on a desktop. Installed are:
cups-2.1.4-x86_64-2_slack14.2
cups-compat32-2.1.4-x86_64-1compat32
cups-filters-1.9.0-x86_64-2
cups-filters-compat32-1.9.0-x86_64-2compat32
cups-pdf-3.0.1-x86_64-1_SBo
pycups-1.9.73-x86_64-1

I've no problems with the HP LaserJet 5, but do with the Dell C1740NW color
laser printer. The latter used to work, but a re-installation of the core OS
blew away the driver.

The Dell is a re-branded Xerox 6000B printer and I installed the Xerox
driver.

I can ping the printer's LAN IP address and CUPS sees the printer. But when
I try printing a test page the effort stops with the message "filter
failed." When I look at the printer maintenance menu option "Set default
options" the entire page is in French, but I recall enough to know the only
options to be reset are the two at the top: activate and set paper size to
letter.

How can I find which filter failed and how would I fix the problem?

TIA,

Rich