Trying to list MySQL DB tables

[Anon]

I am using a portion of a script from Meloni's book, but I keep getting an error.

The variable $dbs, is set to my database.
Here's the troublesome (and rather simple) code:

<?

$db_num = 0;

// line 36 is next
while ($db_num < mysql_num_rows($dbs))
{
$db_names[$db_num] = mysql_tablename($dbs, $db_num);

$db_list .= "$db_names[$db_num]";

echo "<BR>DB list = $db_list<BR>";

$tables = mysql_list_tables($db_names[$db_num]) or die ("Couldn't list tables.");

echo "<BR>table(s) = $tables<BR>";
}

?>

Successful connection!
Warning: Supplied argument is not a valid MySQL result resource in /usr/local/plesk/apache/vhosts/mydomain.com/httpdocs/db_list2.php3 on line 36

Does anyone know what is meant by this term "valid MySQL result resource" ?

[geo115fr]

Difficult to help without the lines before the line 36. Why providing the following lines, it is useless!

before line 36, $dbs must receive the result of a mysql command (typically mysql_query).