View located in different default folder

Yes, it's a security risk. So now you need to patch the form that generates that error.
If you are using a standard <form> tag, you can add the hidden field from the manual or start using the Form Helper.
If you are using Ajax/Javascript, search this forum. There are plenty of information about that topic already.

Codeigniter manual: Cross-site request forgery (CSRF)
The Open Web Application Security Project: Cross-Site Request Forgery (CSRF)