Ubuntu Classic on NattyNarwhal generates problem in policykit-1-gnome

Binary package hint: policykit-1-gnome

RELEASE: Ubuntu 11.04
PACKAGE: 0.99-1ubuntu4 (policykit-1-gnome)

Attempting to launch Ubuntu Classic on NattyNarwhal, resulted in the following error messages:
Application Problemttempting to launch Ubuntu Classic on NattyNarwhal, resulted in the following error message:
1) Sorry, Policykit AuthenticationAgent closed unexpectedly.
2) Problem in Policykit-1-gnome.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: policykit-1-gnome 0.99-1ubuntu4
ProcVersionSignature: Ubuntu 2.6.38-7.39-generic 2.6.38
Uname: Linux 2.6.38-7-generic i686
Architecture: i386
Date: Sun Apr 3 14:11:31 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta i386 (20110330)
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: policykit-1-gnome
UpgradeStatus: No upgrade log present (probably fresh install)