Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/e9b1cbb5543c4e8e83ae0c6b8ec1fce4.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563