One possible cause is the existence of a registry key which should not be present in Desktop Authority. This may happen if an issue occurs during the Desktop Authority Update Service upgrade process which can cause the old value to not be removed.
Verify if the server affected has the Desktop Authority Update Service installed.
If so navigate to this registry key and delete it:
Then log off and log back into the Server.
The script should now run properly without the error message.
NOTE: Technical Support does not provide support for problems that arise from improper modification of the registry. The Windows registry contains information critical to your computer and applications. Make sure you back up the registry before modifying it. For more information on the Windows Registry Editor and how to back up and restore it, refer to Microsoft Article ID 256986 "Description of the Microsoft Windows registry" at Microsoft Support.