Call a plugin in a library..

[eluser]GSV Sleeper Service[/eluser]
try this

Code:

function setChaptcha()
    {
        $vals = array(
            'img_path'      => './asset/captcha/',
            'img_url'       => base_url().'/asset/captcha/',
            'expiration'    => 3600,// one hour
            'font_path'         => './system/fonts/georgia.ttf',
            'img_width'         => '150',
            'word'            => random_string('numeric', 6),
        );
        $cap = create_captcha($vals);
        print_r($cap);
    }

you'll have some debug info on your screen, copy that and paste it back here.