If you have replaced CUPS with LPRng and configured the
printer-admin module you receive the following error
when you submit the changes.
The spool directory /var/spool/cups does not exist on
your system, which indicates that the LPRng print
system is not installed. Either install the software
for your chosen print system, or use the module
configuration to change it.
Workaround: Just simple create a dir /var/spool/cups
Fedora 1 & RedHat 9