For many people submit by e-mail can never work, because their PC is
not set up to send email. For example, countless millions use only
Hotmail, Gmail, Yahoo or similar.
It's also possible you set options (like "submit whole PDF") that
don't work with the free Reader.
It's best to think of "submit by e-mail" as something to help you in
the prototyping before moving on to a proper web-based solution.
Aandi Inston