Error printing in KDE (IPP client-error-bad-request)

Ubuntu 10.10, WHERE 4.6. Prints fail silently, but the record of Cups (/var/log/cups/error_log) contains an error:

Returning IPP client-error-bad-request for Print-Job (ipp://localhost:631/printers/Canon_MX310_series) from localhost

and above:

Syntax error on line 16 of printers.conf.

Possibly a KDE Printer Configuration error.

Solution:

sudo stop cups;
sudo perl -pi -e 's/^JobSheets.*/JobSheets none none/' /etc/cups/printers.conf;
sudo start cups;