Same in FC15.
I believe the root cause has to do with polkit-gnome-authentication-agent-1 being unable to start *when a desktop environment other than the default at install* is in use.
I started out with Gnome3, but am now using Gnome Classic with Compiz. Perhaps most relevantly, if I switch back to Gnome3 packagekit prompts for authentication and installs packages as expected.
Authentication Agent is selected in the "Startup Programs" tab of the gnome-session-properties panel, but is not running.
When I attempt to start it manually via:
$ sudo /usr/libexec/polkit-gnome-authentication-agent-1, I get the message:
(polkit-gnome-authentication-agent-1:23011): polkit-gnome-1-WARNING **: Unable to determine the session we are in:
GDBus.Error:org.freedesktop.ConsoleKit.Manager.Gen eralError: Unable to lookup session information for process '23011'
When I attempt to start it manually via:
$ su
# /usr/libexec/polkit-gnome-authentication-agent-1, I get the message:
g_dbus_connection_real_closed: Remote peer vanished with error: Underlying GIOStream returned 0 bytes on an async read (g-io-error-quark, 0). Exiting.
Terminated
This issue is being tracked in
https://bugzilla.redhat.com/show_bug.cgi?id=638344