Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/d2c5e1a6266e5be989b79046864a9ca0.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563