Wmi sometimes do not have the counter it should have.Servers with same configurations miss some wmi class.
Strange things can happen with WMI.
I have the solution, recreate:
1. Stop the WMI(Windows Management Instrumentation) service
2. Deleter %windir%system32wbemrepository*.*
3. Start WMI (Windows Management Instrumentation) and Microsoft Exchange manager
4. Wait untill ..wbemrepositoryFPOBJECTS.DATA Stops to grow, about 5MB
5. Run: wmiadap /f
6. Rstart WMI(Windows Management Instrumentation) service the OBJECTS.DATA should have about 10MB
Try your WMI query again…