MailChimp Newsletter Sidebox

[ParseRaider]

It's almost certainly the form action part of your \includes\languages\english\extra_definitions\mailchimp_sidebox_defines.php, line 10

Drop the http:, e.g '//YourSite.us1.list-manage.com/subscribe/post' instead of 'http://YourSite.us1.list-manage.com/subscribe/post'

I did and still get error:
define('BOX_MAILCHIMP_NEWSLETTER_URL','//ultimatepicklejar.us12.list-manage.com/subscribe/post');

This is line 851 of page source for mail list clicking subscribe with no email address in the box:
<form action="http://ultimatepicklejar.us12.list-manage.com/subscribe/post" method="POST">

Adding an email address works but warning is still there.

I contacted MailChimp and they suggested adding Wufoo service for another $10 a month I guess...