If the installer did not select the Cups subsystem when Ximian is
installed, the XD cannot manipulate the printing subsystem. Cups must
be configured.
As root (with a current X display), run:
# /usr/bin/redhat-switch-printer
...select CUPS, and then fix the services:
# service lpd stop
# service cups start
# chkconfig cups on
Now you can configure the printer in Cups: