Have you tried to reinstall a theme on your GNOME desktop?
And the theme manager is giving you this error "Cannot move folder over folder".
This is actually a software defect of GNOME 2.24.1 (bug 562371)
The program is not able to overwrite or replace the theme directory.
If you want to know what is your version of GNOME go under the "System" menu and then select "About GNOME".
You could find more informations about this GNOME bug at bugzilla.gnome.org.
They say that the problem has already been fixed and will be included in the next version of GNOME (probably the 2.26.x will be out on March).
rm -R -f $HOME/.icons/UltimateGnome/