After installing the user-themes extension (using the GNOME extensions web site) on Ubuntu 12.04, Advanced Settings won't launch.
When I run it in the terminal, I get this error:
(gnome-tweak-tool:2357): GLib-GIO-ERROR **: Settings schema 'org.gnome.shell.extensions.user-theme' is not installed
Trace/breakpoint trap (core dumped)
How can I fix this?

gnome-tweak-tool(the actual command to run Advanced Settings), and add the output to your question. – iBelieve Feb 6 at 16:36gnome-tweak-tool, copy everything that is displayed on your terminal. Click the edit link under your question, and paste the text into it. Thanks! – iBelieve Feb 6 at 17:12