submit form and weird 404 error

Best thing to do here is to check your error log files to see what is causing the error.

Also make sure that you followed all the CodeIgniter 3x upgrade steps.

Make sure that you set the base_url in ./application/config/config.php

Make sure that Controllers and Libraries are ucfirst uppercase named.

What did you Try? What did you Get? What did you Expect?

Joined CodeIgniter Community 2009.  ( Skype: insitfx )