PHP & MySQL problema !!

<?php
$con = mysql_connect("localhost","*******","*******");
if (!$con)
 {
 die('Could not connect: ' . mysql_error());
 }

mysql_select_db("*****", $con);

$result = mysql_query("SELECT * FROM persona");

while($row = mysql_fetch_array($result))
 {
 echo $row['FirstName'];
 echo "<br />";
 echo $row['LastName'];
 echo "<br />";
 }

?>

Error:

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in /usr/local/psa/home/vhosts/****.lv/httpdocs/dabut.php on line 12

palidziet !!!!