Registry Editor could not set security in the key currently selected, or some of its subkeys. These keys do not give you access to change security information.
Since security settings for a key affect its subkeys as well, you must have permission to change security information for the key and all its subkeys in order to change security information for the key.
Ask your network administrator to give you the appropriate permissions and try again. Or, log on as a different user, for example as an Administrator, and try again.