'Invalid class / Provider Failure' on running Performance queries

Hi, I'm trying to run the following WQL using WMIC from command prompt:

wmic PATH Win32_PerfFormattedData_PerfProc_Process GET
IDProcess,VirtualBytes,WorkingSet

and it's returning something like:

ERROR = 0x80041010

Description = Invalid class

Facility = WMI

instead of the values requested. Sometimes it returns also "Description =
Provider Failure".

I'm using a WinXP machine with SP1 and .NET framework 1.1 installed. Do you
think there might be something wrong in the WMI repository? I've also tried
the query from a script and returns the same error.

Regards,

Christopher Attard