If you are still having problems with the email backup feature, i have posted a solution to this problem as i also run into it before. Even if you dont have the problem it would be nice to update your PHPMailer( the class wordpress uses to send email) from the old one v1.73 to the newest v2.2 . It is best to use it with Gmail. I do and i have daily backups sent to my email with no probs.
Read this post on how to send bacups to your email via Gmail SMTP and do not forget to make a backup copy of your WP-backup plugin, in case something goes wrong.
