Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/45e9e539c4a1e1e53cfd4f6e939f7b69.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563