The WinUser account will require more than local admin privileges for WMI
to work, unless it's the actual "administrator" account that you're using.
This link is not a complete guide (
https://support.zenoss.com/ics/support/default.asp?deptID=16059) but it
will get you rolling in the right direction. Of course it wouldn't hurt to
see if it's working with the "administator" account just once or twice to
verify WMI is working correctly on your server.