Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/ee53b911e8a6d72842e97edd2369e983.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563