[Plugin: Contact Form 7] Strange file bug

I’ve had this problem for some time now, I think it appeared when I updated WP to 3.3.

The form works perfectly, but when an image is selected to be uploaded – The submit button stops working. It’s not loading/submitting anything and I’ve tried figuring out the problem with Firebug, but the submit form doesn’t seem to change. Without submitting an image it works fine.

Anyone experienced anything like this?
Here’s the form: https://hasitleaked.com/add-an-upcoming-album/

Any help and I would be really grateful!

https://www.ads-software.com/extend/plugins/contact-form-7/