I'll need to write up something (later) but I'll give you some help.
You can ONLY configure email using the AC3/Pro buttons (you can't do it from AquaNotes (unless you are using AquaNotes to send the email; which I know you are not).
Menus are:
Setup->Net Setup->Email Setup
and configure the following:
SMTP Server
From Address - (usually your email address)
To Address - (usually your email address)
Email Auth - (on/off - tells AC3 if you need to logon to the SMTP server)
Auth User
Auth Password
Alarm - Name of timer that, when on, triggers an email to send
After this try a test and if that doesn't work log onto the AC3 (using telnet) and enter the following command, 1 per line:
cons
1 maild
mail
You will/should get a verbose log of a test email session which usuallywill point to the missing/incorrect parameter.
Hope this helps!