Submit Button on Registration Page No Longer Works After Update

Our registration page has been working perfectly since installation; however, it has stopped work as of today. A new customer can complete the registration, but the Submit button does nothing. No error message or redirection occurs; it simply sits on the registration page.

After checking the plugin, it appears as though an update to the plug-in may have caused this issue. We have not made any system changes that could have caused this problem. Please advise.