I know absolutely nothing about Cyrus, but a Google search of your error pops up
this page. Did you happen to see this? It states they were able to fix the issues by uncommenting other service lines in the cyrus.conf file. Specifically, they said the imap service is required for login.
Also, looking on SBo, there is a
README.SLACKWARE that gives some additional commands on getting it set up. Have you ran those?