I have this same error. But mine arose because the installed theme did not appear in the list of themes when it was not in use. Its folder was in ~/.themes, but it didn't show up in "appearance preferences". I deleted the ~/.themes folder and reinstalled. It still didn't show up, but could be used until I rechanged the theme.
-- Installation for theme "name_of_the_theme" failed. Can't move directory over directory https://bugs.launchpad.net/bugs/344343 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs