Problems with e-newsletter template

Hi! I have a problem with the newsletter-template. I get this message:

Warning: Creating default object from empty value in /xxxxx/xxxxxxx/xxxxx/wp-content/plugins/e-newsletter/email-newsletter-files/builder/class.builder.php on line 621

I use DMS (pagelines) and a few wpmudev-plugins. The deactivation of the plugins makes no difference.

Thank's for your help!

Petra