Unauthorized: Cannot manage printers using lpadmin or cupsctl

[era]

Binary package hint: cups

Default Lucid install. My main user account has sudo privileges and belongs to group lpadmin, but all my attempts at managing my printer using cupsctl and lpadmin fail with

lpadmin: Unauthorized

both for my main user id and with sudo.

This is a remote Windows printer shared over Samba.

era@fsopti607:~$ cupsctl --debug-logging
cupsctl: Unauthorized

era@fsopti607:~$ sudo cupsctl --debug-logging
[sudo] password for era:
cupsctl: Unauthorized

era@fsopti607:~$ lpadmin -p floor2_hpmf2 -o auth-info-required=negotiate
lpadmin: Unauthorized

era@fsopti607:~$ sudo lpadmin -p floor2_hpmf2 -o auth-info-required=negotiate
lpadmin: Unauthorized

era@fsopti607:~$ type -all lpadmin cupsctl
lpadmin is /usr/sbin/lpadmin
cupsctl is /usr/sbin/cupsctl

era@fsopti607:~$ dpkg -S /usr/sbin/lpadmin /usr/sbin/cupsctl
cups-client: /usr/sbin/lpadmin
cups-client: /usr/sbin/cupsctl

era@fsopti607:~$ apt-cache policy cups-client
cups-client:
  Installed: 1.4.3-1ubuntu1.2
  Candidate: 1.4.3-1ubuntu1.2
  Version table:
 *** 1.4.3-1ubuntu1.2 0
        500 http://mirrors.nic.funet.fi/ubuntu/ lucid-updates/main Packages
        500 http://mirrors.nic.funet.fi/ubuntu/ lucid-security/main Packages
        100 /var/lib/dpkg/status
     1.4.3-1 0
        500 http://mirrors.nic.funet.fi/ubuntu/ lucid/main Packages

era@fsopti607:~$ groups
era adm dialout cdrom plugdev lpadmin admin sambashare

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Narcis Garcia (narcisgarcia)]

Reproduced with Ubuntu 14.04 in a chroot environment.
Also tried adding "root" account to "lpadmin" group.

[Till Kamppeter (till-kamppeter)]

Please attach your /etc/cups/cupsd.conf and /etc/cups/cups-files.conf files. Thanks.

[Launchpad Janitor (janitor)]

[Expired for cups (Ubuntu) because there has been no activity for 60 days.]