Win32_PerfRawData_PerfOS_System Class not found

All,

We have experienced a number of servers returning NO Wmi Data for  System Uptime SystemUpTime.

Upon further investigation we found the the servers do not have the Win32_PerfRawData_PerfOS_System WMI class. 

I am not sure if anyone has a corrective action.  I have not found out to get the this class registered on the system.

Any assistance is appreciated.