Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/e9463f0cd3f7af857ba8e35b7ce3b2fd.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563