Issue - Form_Validation > Setting Error Messages > set_rule()

What version of CodeIgniter are you running? I tried out your rule and I see the custom message in 3.1.10.

For the heck of it, have you tried overriding the whole form_validation with

PHP Code:

$this->form_validation->set_message('required', 'Test message.'); 


or something similar? Just for testing purposes of course. Dependent on that result, it helps steer you in the right direction with what might be the issue.