Known issue in Microsoft Windows which is covered by the following MS article:
How To Fully Uninstall a Performance Monitor Extension
http://support.microsoft.com/default.aspx?scid=kb;en-us;247226
Per the above document, you need to remove the open value from:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DHCP server\performance
by following the steps below:
To completely remove a performance monitor extension, first identify the service name of the product that supported the custom counters. In this case "DHCP server".
Use RegEdt32.exe to traverse to the following subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DHCP server
Select the "Performance" subkey and from the Edit menu, click Delete. This action deletes the Performance subkey and all its values.
Please make a backup of the registry before modifying it. You should reboot the CM server after modifying the registry for the change to take effect.