During the upgrade process of my home machine from Fedora 16 to 17, a lot of my gnome-shell-extensions stopped working.
After poking around a bit, I decided to take a "slash and burn" approach to all the installed extensions (and there left over config files)
yum remove gnome-shell-extension*
The two places the leftovers hide are
I simply removed these directories, restarted gnome shell ( alt+F2 and type 'r' and press enter ) and re-installed gnome-tweak-tool
Careful when executing rm -rf
rm -rf ~/.local/share/gnome-shell/extensions/* rm -rf /usr/share/gnome-shell/extensions/* yum install gnome-tweak-tool
This should get you to a clean slate, and ready for https://extensions.gnome.org/ which is what I use to install all my extensions.