Have you installed the Formidable Forms plugin too? It’s possible that is the error you are receiving. Otherwise, if you do have the Formidable Forms plugin installed, then we may need to take a look at your installation, complete this form if login is possible.
Or, let us know if not and we will attempt to troubleshoot through screenshots and messaging, starting with a screenshot of the Under The Hood tab and the Activated Forms tab. You can use the link above to send the screenshots to us.
We remain at your service.