I have been trying to activate the theme Celestial - Lite. When I am logged in as Administrator, everything seems to look as it should. The theme has been activated. If I log out and look at the blog I see my old theme Duster.
I was wondering if the problem was caused by a plugin but when I deactivate them the same problem of different themes occurs.
The blog can be found here: http://mfcarter.net/blog/