Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/e5c0f2aba1e42a930f9da00e9134d6a4.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563