The latest NGUI public release is 3.0.6 f7, not f1. And that's the version that's on the Asset Store.
With the latest version (f7), and the function replacement I posted (NGUITools.SetActive), all you need to do to activate something is:
NGUITools.SetActive(targetObject, true);
I had this problem with the Widget Wizard.
In my case it was a Unity Window problem.
Try going into Window -> Layout -> Revert Factory Settings
Hope that helps.
Ps. I've always found that support has been excellent!