Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/e0e5d6ccf21ecf30b7c5f5ecc54ee3c2.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563