Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/cd9db5dd2284e82039d42b9171fb6c32.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563