Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/0903daa1c2024980494ae1f8c96c5419.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563