It’s possible that your form include “page break” without fields. when you save as a Submission-Enabled PDF form, it will show up as blank pages, same as your designed. Would you please share me your form to help you solve a problem, if it’s convenient?
Thank you for your reply.
I've not put any page breaks in - I even tried deleting the ones that are there and then re-inserting them.
I'm not sure how to share my form with you!
Make sure that you view the form design in "Page View"
From the Design Tab go to View > Page View
You can also see and switch views in be bottom right corner of FormsCentral
Once in Page View you might see Page Break elements that you didn't see on the Web View. The Page Break element is special in a sense that adding a Page Break in Web view only affect the HTML form and a Page Break in Page View only affects the PDF form.
If this does not fix your issue you can find instructions on how to share the form here : http://forums.adobe.com/docs/DOC-2462