A couple of days ago I got bit by a nasty and pretty dumb bug in dbus on Fedora Core 6: the service would just hang forever on startup.

To make a long story short, it all goes down to some interaction (I have no idea about) between dbus and ldap (of all things): if the ldap server is not available the servie just hangs.

To make the bug go away simply disable the use of ldap for “User Information” in system-config-authentication. It looks like you can continue to use it for authentication, fortunately.