I double checked everything for you. There was a misplaced comma that gave you the sql error. Zip is updated.
However on to your header thing. Since you get that after adding the user it is safe to assume your problem is combination of things on your install. Here is the code that your install does not like.
$html -> send_header($ubbt_lang['NEW_CONFIRM'],$Cat,0,0,0,0);
$html -> admin_table_header("{$ubbt_lang['NEW_CONFIRM']}:");
$html -> open_admin_table();
echo "
<tr>
<td class="lighttable">
{$ubbt_lang['NEW_BODY']}
</td>
</tr>
";
$html -> close_table();
$html -> send_admin_footer();
?>
You could try commenting out everything here except the send_admin)footer and see if that gets rid of your problem.
