404 & submit not working properly

I’m getting a lot of 404-errors on

/wp-content/plugins/contact-form-7/includes/js/jquery.form.min.js?ver=3.51.0-2014.06.20

I’m not sure if it has to do with the problem that after submitting a form, the wheel keeps turning and the visitor is not directed to the ‘thank-you’-page that is reported earlier on this forum. (the form is delivered though, and also stored in Flamingo, but the visitor might think submitting the form is unsuccessfull).

Hope this can be resolved soon.