chyba v sql

kod

<?php require "db.php";
$find_theme = mysql_query("SELECT * FROM themen ORDER BY id DESC");
$themen = $_GET["theme"];
if($themen!=NULL) {
include "theme.php";
}else {
?><?php while($ok=mysql_fetch_array($find_theme))

{

?></h3>
<div style="text-align: left;">
<center>
<center></center>
</center>
<br>
<table
style="left: 23px; width: 522px; text-align: left; margin-left: auto; margin-right: auto;"
border="1" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td colspan="1" rowspan="1"
style="text-align: left; background-color: rgb(255, 255, 204); vertical-align: top;"><a
style="color: rgb(255, 102, 0);"
href="index.php?page=forum&theme=<?php echo $ok[id];?>"><?php echo $ok[theme];?></a>
<div style="text-align: right;"><?php echo $ok[autor];?>
/<?php echo $ok[datum];?> </div>
</td>
</tr>
</tbody>
</table>
<br>
<?php }?><br>
<?php }?></div>

v tom cernym radku mi to pise chybu nevim proc chyba je

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in

ok diky za pomoc

no kdys dam to ORDER BY id DESC tal to jede jenze ja chcu to nejnovejsi navrchu

ok skusim

ne porad to nechce jit

prosim pomocte