My problem is I'm trying to install a new theme (system > preferences > appearance)

Well, when I install the theme it says "GNOME Theme Mac4Lin_GTK_v0.4 correctly installed" but the theme doesn't pop up. Then when I try again it says "Installation for theme "Mac4Lin_GTK_v0.4" failed. Can't move directory over directory"

Then I tried going to my home folder and doing (ctrl+h) and deleting my .theme files and .icon files.

Still doesn't work when I try again.

any help would be greatly appreciated. Thanks