Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/22e8451e24b087c61e02c8127c872ebe.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563