Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/fdfa8f066c14969b8f9c2cb47aad6a90.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563