problems with connection

[Mauro Allende]

i have problems with the following php script:

<?php
$db_host = "localhost";
$db_user = "php";
$db_password = "msa";
$db_name = "bdprincipal";
$link = mysql_connect($db_host, $db_user, $db_password);
if (!$link) {
die("No se pudo conectar: " . mysql_error());
}
echo "Conección exitosa";
mysql_close($link);
?>

The Internet Explorer Browser shows:

Fatal error: Call to undefined function mysql_connect() in C:\Archivos de programa\Apache Group\Apache2\htdocs\test_connect.php on line 6

Please, help me. Thanks. Mauro