the plugin seemed to work ok, did everything including send email to subscriber. but when i visited as admin the link "Manage Subscriptions", there were NO subscriptions! so i guess it didnt actually register the subscriber in database?
i dont think its related, but i also use plugin AntiSpam Bee http://wordpress.org/extend/plugins/antispam-bee/
http://wordpress.org/extend/plugins/subscribe-to-double-opt-in-comments/