Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/1b3385bee6e20e57e28a39b98eb8e46a.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563