I believe that's one of the limitations with later versions of Adobe applications: only Adobe-produced PDF forms can have their contents saved to a file.

As for your previous post, if you can actually get this to work with a recent version of Adobe Reader (7 and up), I'd be very interested to take a look at the document.
_________________________
Technical Product Manager
I don't want to achieve immortality through my work; I want to achieve immortality through not dying - Woody Allen