Can you please tell me what program the recipient is using to open the form? There are 2 situations where the "blank" fields occur commonly:
1) The recipient is opening some documents in the desktop Adobe Reader with Field Highlighting enabled. Some forms have fonts or use text that we can't yet encode correctly in the Mobile Reader. For these fonts, we use an image snapshot of the field and the desktop Reader hides these when field highlighting is turned on. If you are having this problem in the Desktop Adobe Reader, please have the recipient disable field highlighting. This is an issue we hope to address in coming Mobile Reader releases.
2) The recipient is viewing the document on a mobile device without Adobe Reader. The built in PDF viewing on the iPhone/iPad Mail app does not display form data. If your recipient is viewing the form on a Mobile Device, they should choose "Open In.." and chose Adobe Reader.
I hope this solves your issue!
There should be a purple bar across the top of the document. In the right hand side of that bar should be a button that says "Highlight Existing Fields". That button toggles the highlights. I'm sorry for this hassle - this is something we plan to fix in the coming months, though it's a complicated issue so it may take some time. Please let me know if this does not work. Thanks!