Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/697df4042c7c251847e354e5d59c6c41.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563