Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/9f6a2940f289704fd60fa6106c5f7c49.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563