You could try manually removing the CUPS PID file (or rebooting, which should accomplish the same thing).
I just updated the HowTo in correctly specify the repository name after "--enablerepo=", so maybe it works differently now...
Otherwise you should open a bug report at Bugzilla and hope for more useful input that I can provide

(I'd suggest posting the new bug in 'SME Contribs', package='Unknown' since I see no entry for
cups,
smeserver-cups or
e-smith-cups, then add the email address of the maintainer from the HowTo in the CC field)