I was getting the message An illegal choice has been detected. Please contact the site administrator. when submitting forms, and more annoyingly when doing an AJAX image upload on a form.
The problem is caused by the radio buttons that I have on my form. They are set up without a default value but as required. I believe the issue is that if a radio group dosen't have a value set, it doesn't existing within the DOM for the form in question, therefore leading to an error on the form checking.
