i am also facing the same problem. no emails sent - ever!
i have found a bug too. the plugin is displaying
Please log in or register.
log in or register. " />
when browsing as a guest and then happily transforms to a neat button after logging in. hence, it is echoing "log in or register twice" and also displays a naked slash ( / ) along with double quotes ( " ), which i guess is a compatibility issue with either the sufussion theme or some plugin ( qtranslate? i am not sure! ).
i can not pin-point the culprit at the point of writing this as i have several plugins running the show. well, qtranslate does have a questionable past.
OR it could be conflict with some other plugin using jquery?
NOTE : i have enabled and disabled the inline css styles but it did not work.