Hi Kevin,
I recommend that you restart your computer then right-click on the Photo Mechanic installer and choose "Run as administrator". If the problem persists, please contact our support department via email or phone so that we may investigate the issue further.
By email: support@camerabits.com
By phone: +1 503.547.2888
Hours: Mon-Fri, 9:00am-5:00pm [PST/PDT]
-Jerry