Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/04e5125d91406c7c373a9164815c8bc9.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563