Norton Safety Minder crashes when using Fast User Switching

I am running version 2.1.0.21 of Norton Safety Minder on Windows XP (SP2).  I have four user accounts setup in Windows and two of them are being monitored by NSM.  If I use Fast User Switching to switch between two accounts, NSM crashes.  (It may not happen every time, but it seems to be frequent.)  The tray icon will still show a message if you hover over it with the mouse, but it will no longer bring up a menu if clicked on, and an e-mail is sent to the monitoring account indicating that the NSM has been disabled.

 

Is this a known issue?