Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/5ae8aa7d238936f93b4d910c8ea753e5.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563