eNewsletter Signup Form

We have the eNewsletter plugin installed in http://www.statswhisperer.com. However over the weekend the Sign-up form does not display. The short code is there but it does not display anymore. The form should be on the bottom of this page: http://www.statswhisperer.com/newsletter/
We did not make any changes to the site. I can give you Admin rights to the site if needed.