Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/083864c6597d8f0c3adefd5d4963a2b2.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563