When I go to
and try to start the theme manager I get the following answer:
No themes could be found on your system. This probably means that your "Theme Preferences" dialog was improperly installed, or you haven't installed the "gnome-themes" package.
The themes were correctly installed in /usr/share/themes
All other users, including root, on the system can change their themes without any
problem. Help on this issue would be much appreciated.