Frustrated after spending an hour on trying to troubleshoot. Apparently the developer indicates two lines to change to a send-mail.php file in their plug-in admin file, and then another person says it's a problem with 3.4's mail function.
I get a 'are you sure you want to send this?' message without any button to send.
Upon suggestion of another person I installed the WP-Mail-SMTP plugin but that didn't help either.
I don't have the time or the inclination to fix this, I just want an email subscription plugin works.