Ok, just noticed that changing the cups server from localhost to 127.0.0.1 in the print configuration dialog of kprinter fixes the problem (system options => cups server => host). No more connection errors and the printers are visible.
-- Cups printing fails after update to kde-3.5.5 https://launchpad.net/bugs/65665 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
