Find your username in the list of :"group or user names"... and select it. Then click "edit" to change permissions and make sure all check boxes are checked. In particular "full control" and "read" and "write". Even if you are an administrator on your computer and Administrator permissions has all checkboxes checked.... you need to make sure your individual username ALSO has permission boxes checked in the security tab. Be sure to hit "apply" after you check all the boxes and then go back in and make sure all the boxes are checked. That should fix the problem.
