Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/e1ed9a7d0e998540971fb0b1f22bc0de.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563