Can you tell me a little bit more about your workflow. Are you trying to save your form as PDF from the Formscentral web app or the desktop AIR application? What level of formscentral account do you have? Do you have Acrobat XI installed on your system?
I have Acrobat XI Pro installed on my laptop and an Adobe full Creative Cloud license. When I launch Arcrobat XI Pro and create a form, it launches the Formscentral web app. This app will not allow me to save my work by exporting to PDF. I did not even know that there was a desktop AIR version of Formscentral - would that make a difference?