I am having similar problems with 8.0.020.000. I downloaded it after after receiving an update notice from ZoneLabs. I updated from 7.0.483.000. The required reboot went OK, but Windows (XP Pro SP3) stalled on on subsequent shutdowns. Windows stalled repeatedly on shutdown: sometimes it would stall on "Saving your settings...", sometimes on "Windows is shutting down...". Sometimes it would shut down after 3 or more minutes; sometimes it wouldn't.
I tried doing a clean reinstall of 8.0.020.000. Same results.
I reverted to a clean install of 7.0.483.000 (I had saved the installation program), and now I can shut down in a few seconds again.
BTW: 8.0.020.000 would not let me revert to 7.0.483.000. I needed to uninstall 8.0.020.000 first.