After upgrading to the latest kernel of Ubuntu, I was not able to access the admin applications like Network, Date and Time settings, etc. It complains that the user doesn't have permissions to access the application settings.
Verified the user that I logged on with, it has admin privileges so it was somewhat weird that I was not able to access these apps. Any way, the following trick worked:
Reinstalled D-Bus which worked like charm. From the terminal --
sudo /etc/init.d/dbus stop
sudo aptitude reinstall dbus
sudo /etc/init.d/dbus start