The previous build introduced a working screensaver check by talking to gnome-screensaver via dbus. Unfortunately, the error case was using g_error instead of g_warning, causing notification-daemon to abort if gnome-screensaver is not running. See bug https://bugzilla.redhat.com/show_bug.cgi?id=529592

Fix tested by myself. Test consists of

killall gnome-screensaver
killall notification-daemon
/usr/libexec/notification-daemon
notify-send test test
verify that the notification-daemon is not aborting