Solution one: install Microsoft hotfix.
A bug of Microsoft might cause a WMI issue. This bug impacts windows 7 and windows server 2008 R2. Please refer http://support.microsoft.com/kb/2655244 to see more details and download hotfix. Attachment is the hotfix from Microsoft for x64 windows 7 and windows server 2008 R2.
Solution two: change settings in windows registry.
Follow next steps to solve the WMI issue.
1. Find HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\forceguest in the Windows registry, and set it to 0.
2. Go to HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server in the registry and create a DWORD-value key named “AllowRemoteRPC” and set its value to 1.
3. Restart the device to implement the changes..
Additional details are located at: http://en.community.dell.com/techcenter/networking/nms/w/wiki/6785.troubleshooting-how-do-i-solve-the-access-denied-error