framework error: Cannot call method 'on' of undefined

I recently upgraded Sencha Architect to 3.1 from 3.0.4. Since then, my project refuses to show in Design View with the following error:

Framework Error: Cannot call method 'on' of undefined.

I emailed architect.feedback at sencha dot com on the 20th Jan with a link to the project that I uploaded to my dropbox account. Can you let m know if anyone has received and/or looked at my issue?

framework error: Cannot call method 'on' of undefined