Possible Duplicate:
Warning: mysql_fetch_* expects parameter 1 to be resource, boolean given error

I'm having a little practice regarding mysql stored procedures. Here is the php file which calls it:

<?php
include('conn.php');
$cor=$_POST['course'];
$sql="CALL list('$cor')";
$result=mysql_query($sql);



?>

<table>
<tr>
<th>Name</th>
<th>Course</th>
</tr>

<?php 
while($row=mysql_fetch_assoc($result)){
?>
<tr>
<td><?php echo $row['Name']; ?></td>
<td><?php echo $row['Course']; ?></td>
</tr>

<?php } ?>

</table>

Ve burada ben heidi sql bunu çalıştırdığınızda iyi çalışır saklı yordam var:

CREATE PROCEDURE `list`(IN `COR` VARCHAR(50))
    LANGUAGE SQL
    NOT DETERMINISTIC
    CONTAINS SQL
    SQL SECURITY DEFINER
    COMMENT ''
BEGIN
SELECT * 

FROM tb1 
WHERE Course=COR;

END

Please tell me how do I debug this one, I'm having this kind of error:

mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in

Ben sorgu hatalı olduğunu sanıyorum. lütfen yardım.