Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/7ae8b4b856db3d1c46643606f0ba779a.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563