Steps to reproduce the issue

go to website
http://www.nov22.nazwa.pl/ok/okna/installation/index.php

Expected result

Run the istallation

Actual result

Warning: require(/home/nov22/ftp/ok/okna/libraries/ClassLoader.php): failed to open stream: No such file or directory in /home/nov22/ftp/ok/okna/libraries/composer_autoload.php on line 22

Fatal error: require(): Failed opening required '/home/nov22/ftp/ok/okna/libraries/ClassLoader.php' (include_path='.:/usr/share/pear/') in /home/nov22/ftp/ok/okna/libraries/composer_autoload.php on line 22

System information (as much as possible)

Additional comments

I don't know what to do, Joomla installation is fresh, I copied files twice on the server