the second line should not change, but you have a syntax error for the first l;line.
this code:
$kfm_userfiles_address = '../../up/sites/'.$S_SESSION['SiteID'];
should be:
@session_start();
$kfm_userfiles_address = '../../up/sites/'.$_SESSION['SiteID'];
for the other issue, make sure to install the latest version of HTML Editor that is available from the download center.