[MrLister]

This is because that column doesn't exist in the database. Try this

PHP Code:

<?php
error_reporting(7);
chdir ("./../admin");
include ("./../admin/global.php");
    echo "<b>$bbtitle Members:</b>";
    $vbusers = $DB_site->query("SELECT userid,username FROM user ORDER BY username");
    echo "<table border=1><tr><td><b>Username</b></td><td><b>UserID</b></td></tr>";
    while ($vbuser = $DB_site->fetch_array($vbusers)) {
        echo "<tr><td><font size=2>$vbuser[username]</font></td><td><font size=2>$vbuser[userid]</font></td></tr>";
    }
    echo "</table>";
?>

$vbuser[importeduserid] is not even used so the above works exactly the same.