Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/d65d5902e66d1a6eff32a196ea1c7774.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563