Anyone who has managed SMS for any amount of time has inevitably run to into instances of SMS clients not behaving as expected due to WMI corruption.
Up until now the process of finding and correcting issues with the WMI repository has been painstakingly ugly and difficult, though wmidiag helps a bit.
Microsoft recognized the issues with WMI and made several improvements in Windows Vista to address them.
The good news is that Microsoft recently announced they have back-ported the WMI stability fixes from Vista to both Windows XP and Windows server 2003.
See the articles below for the specifics:
933061 An update is available that improves the stability of the Windows Management Instrumentation repository in Windows Server 2003
933062 An update is available that improves the stability of the Windows Management Instrumentation repository in Windows XP