DooGie wroteHave you tried running Regedit then right clicking the entry and selecting Permissions on the drop down list and looking what that shows? If I'm not mistaken Jouni's programmes will not overwrite permissions so if something in the registry is protected you will have to do a manual delete after setting the appropriate permissions.
I agree ...
Some registry keys can not be removed because the currently logged in user has not "permissions" to modify or delete that key. Some keys will not allow any user to modify or delete them.
So you will have to edit the key's Access Control List (ACL).
How to manage that, you can find here
and in the book: Honeycutt, Jerry, "Microsoft Windows Registry Guide", Microsoft Press, Redmond, 2005, p. 203 ff.