Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/d0a37e7584d5b23322e3ca2c676a4f39.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563