What does this PHP error mean?

What does the following error message mean?

Warning: mysql_data_seek() [function.mysql-data-seek]: Offset 0 is invalid for MySQL result index 3 (or the query data is unbuffered) in \\nawinfs03\home\users\web\b1878\rh.slmarble\php\getproductDB.php on line 6
or die('

Code:

if (!mysql_data_seek($results, $num)) 开发者_如何学C{
    echo "<h1 style='padding:10%'>Coming soon!</h1>";
}

I don't think you're query is returning anything. From the PHP manual:

..if the result set is empty (mysql_num_rows() == 0), a seek to 0 will fail with a E_WARNING..

http://php.net/manual/en/function.mysql-data-seek.php