Getting a somewhat similar message in Suse 10.1 and kde 3.5.4 starting last Thursday night (10/5/2006).
Message is:
Unable to retrieve the printer list. Error message received from manager.
Connection to CUPS server failed. Check that the CUPS server us correctly installed and running. Error: localhost: read failed (15).
Not sure what I may have done to trigger this. Have had no problems printing before. Installed 10.1 back in June, and have kept up with updates since that time. Did not notice an update lately that might affect printing.
I have no problem printing out of Firefox, OpenOffice, CrossoverOffice/Quicken, Adobe Reader. They are probably not using kde to print.
I did both the ps command and looked in ksysguard. Both show cupsd running. I forced an update of the cups rpms, deleted and re-entered my printer in Yast. I looked at the logs in /var/log/cups and my limited knowledge did not spot anything. Cups is still at the original version from the 10.1 installation (1.1.23).
Are there any kde/cups experts that can give me some direction?