Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/70299cc1ee5c0b01460de7f4ca06c2af.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563