Problems with Callback Functions and Validation Class

[eluser]Unknown[/eluser]
I had the exact same problem. I was able to get error messages to show by changing

Code:

$this->validation->set_message('numberowners_check', 'Number of Owners must be numeric');

to

Code:

$CI =& get_instance();
$CI->validation->set_message('numberowners_check', 'Number of Owners must be numeric');