This problem occurred for Fedora 16 (Kernel 3.1.6-1.fc16.x86_64), Gnome Shell 3.2.1-2, Gnome Tweak Tool 3.2.1-1 and User Theme Extension 3.2.3-1. You will have a problem on gnome tweak tool’s shell theme can not be enabled.
To fix this problem, you’ll have to change the dconf settings manually. This requires you to know the name of the theme folder in advance.
As of example, if you want to set Faience as your default gnome shell theme, and there is a directory named Faience in ~/.themes/, then you need to remeber the name faience.
Type command dconf-editor to open it. (Install DConf Editor: yum -y install dconf-editor) You’ll see a list of hierarchical controls (in a tree-view) in the left pane, and relevant settings of the selected node on the right pane.
Expand to org > gnome > shell > extensions > user-theme on the left pane. On the right pane you’ll see a key-value pair field with the key named “name”. Double click on the value field for that key, and type the name of the theme directory (e.g. faience in this case). After you set the value, close the editor. You’ll now see the required gnome shell theme.