As some people have found out the hard way, dbus and all programs that connect to it (hal, powersave, avahi, etc) have to be restarted after the dbus 1.0 upgrade. Without restarting, the uuid file in /var/lib/dbus will be missing and applications could exit with a dbus error message. Following the advice from this error message will work out also.
DBUS upgrade requires restarting dbus
2007-02-05 - Jan de Groot