This is great for the original file but doesn't seem to fix it as a proxy rig
Are you getting any error messages in the top info bar?
Also make sure you are running the script in the text editor, and that 'auto run python scripts' is active in the user prefs.
(but I think you would have checked that already)
If you run Blender with a console open you can sometimes get more information about things when they don’t go as planned.