the Path to Pear you enter should take you to the Mail.php file, yes. But it should be a system path, not a relative path.
on my system the path is:
/usr/local/share/pear/
I have no idea what that path should be for your system though. You will need to contact your host for that information.
also, to send an email through Googles servers, you need to connect to the Google smtp server using SSL.
in the email password behavior, use the following for the smtp server:
ssl://smtp.gmail.com