problem saving an excel file

i have a php script to convert a simple query into an excel format
file (tab delimited) which is called mysql-to-excel. on the author's
website when i click on the script i download an xls file, but when i
do the same on my server it just echos back the query without saving a
file. any ideas. here is the script:

include 'config.php';
include 'opendb.php';

$query = "SELECT * FROM information ORDER BY lastname";
$result = mysql_query($query) or die('Error, query failed');

$tsv = array();
$html = array();
while($row = mysql_fetch_array($result, MYSQL_NUM))
{
$tsv[] = implode("\t", $row);
$html[] = "" .implode("", $row) . "";
}

$tsv = implode("\r\n", $tsv);
$html = "