Error: undefined variable

Hello!

I have several forms on my site, and since I updated to the latest version of WP (3.8) and the latest version of Ninja forms (2.3.8) i get an error. On each line it says “Notice: Undefined variable: address_class in /storage/content/28/187028/woodeye.se/public_html/wp-content/plugins/ninja-forms/includes/display/fields/display-fields.php on line 362”. Isn’t the latest versions compatible with each other?

Oh, and I also do use a checkbox, and the bullets is visible all of a sudden. And the boxes align vertical rather than horisontal like they used to before the update.

The website, with the form (http://woodeye.se.preview.binero.se/en/woodeye-5/)

http://wordpress.org/plugins/ninja-forms/