Every time I shut down my PC or log off (Athlon XP 1900+ running XP SP3, so fairly ancient, but still reasonably usable) I get the Windows "End Program" message for Spybot Tray. After a while the message says that the Spybot Tray is not responding and I then have to click on the option to end it manually.

Why is the Spybot Tray not shutting down more gracefully?