Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/9e4faa02f36be775442b94f48e19469a.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563