Why is my Publish button not available?

I am trying to publish a generator for FCPX (10.1.4) out of Motion (5.1.2). My OS X is 10.10.2. However, when I select the "Publish as a Final Cut Generator" option out of the selection box in Motion (see screen shot: http://screencast.com/t/3ybVCuzSq) the "Publish" button become unavailable. What am I doing wrong?

Thanks in advance for your help!