BuddyPress.org

I’d double-check that the admin email is correct at yourdomain.com/wp-admin/options-general.php

Then, make sure that the emails aren’t being zapped by your SPAM filter.

Do you get regular BuddyPress notifications (friend requests, private messages, etc.) to the admin email?

Is your email hosted on the same server as your site? You might try switching the admin email to gmail or whatever to see if the emails go to that other account. Because if your email account is the same as your website domain but you host your email elsewhere (ex. Rackspace, Google Apps), your server might be trying to send the message locally.