Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/bc7a8f8335def7deff06035a8c28e02a.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563