Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/1d95c84af4b7c52e5006e48d2f6e60e1.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563