It appears the issue may have been with a plugin called “Folders”. Deactivated it, and I was successful in activating Cost Calculator Builder. Thanks for your help!
It’s not working for me, either. WP ver 3.9.1, plugin ver 1.1.0.2. I get a 500 Internal Server Error when trying to edit my contact forms. Disabled “Contact Form 7 – Dynamic Text Extension”, now I can edit my forms.
