To clarify, the error that is thrown reads, "NotAllowedError: Security settings prevent access to this property or method."
In the Acrobat XI SDK release notes:
And the exportXFAData method notes the following in its quickbar:
So, if the "F" doesn't apply, then what's the problem? I've tried putting the method in a folder-level script with an enclosing app.beginPriv() and app.endPriv(). Still doesn't work.