If you have been getting
Unable to retrieve the printer list. Error message received from manager:
Connection to CUPS server failed. Check that the CUPS server is correctly installed and running. Error: the IPP request failed for an unknown reason.
when trying to run kdeprint here is a fix:
and comment out the line
(Its within the first 20 lines - line17 on mine)
Then open kdeprint. The error should be gone