Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/965b2e3e0e413c73c3e0c032b1e84055.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563