system-config-printer asks for the root log-in details

When I click on Printer in the System menu I am asked to enter the root password. The root account isn't even enabled.

Running "gksudo system-config-printer" avoids this prompt.

Why is it asking for root credentials in the first place instead of invoking sudo?

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: system-config-printer-gnome 1.3.1+20110222-0ubuntu16.3
ProcVersionSignature: Ubuntu 2.6.38-11.50-generic 2.6.38.8
Uname: Linux 2.6.38-11-generic x86_64
NonfreeKernelModules: fglrx wl
Architecture: amd64
CupsErrorLog:
 E [01/Oct/2011:22:20:05 +0100] Returning HTTP Forbidden for CUPS-Get-Devices (no URI) from localhost
 E [01/Oct/2011:22:20:11 +0100] cupsdAuthorize: pam_authenticate() returned 7 (Authentication failure)!
 E [01/Oct/2011:22:20:12 +0100] cupsdAuthorize: pam_authenticate() returned 7 (Authentication failure)!
 E [02/Oct/2011:01:14:39 +0100] Returning HTTP Forbidden for CUPS-Get-Devices (no URI) from localhost
Date: Sun Oct 2 01:26:09 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
Lpstat: device for Samsung-CLP-300: lpd://192.168.0.16/p1
MachineType: Acer Aspire 5551
PackageArchitecture: all
Papersize: a4
PpdFiles: Samsung-CLP-300: Samsung CLP-300 Foomatic/foo2qpdl (recommended)
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-11-generic root=UUID=bcf30c65-9b6f-492c-896c-332ab1682c02 ro
SourcePackage: system-config-printer
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/11/2010
dmi.bios.vendor: Acer
dmi.bios.version: V1.05
dmi.board.name: Aspire 5551
dmi.board.vendor: Acer
dmi.board.version: V1.05
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: V1.05
dmi.modalias: dmi:bvnAcer:bvrV1.05:bd05/11/2010:svnAcer:pnAspire5551:pvrV1.05:rvnAcer:rnAspire5551:rvrV1.05:cvnAcer:ct10:cvrV1.05:
dmi.product.name: Aspire 5551
dmi.product.version: V1.05
dmi.sys.vendor: Acer