Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/30c4f0248d847af39cb67b1e39b80132.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563