Website :S

Hello, please i need urgent help, i have decided to open my gunz server, i followed all steaps, all. And i setup my page like the guide, i have revised 15 times, if i go to localhost it comes this:

Fatal error: Call to undefined function mssql_connect() in C:\AppServ\www\config.php on line 2

Please help me so, :(

Well what is line 2? Give the code/

This is the code:

<?php
mssql_connect("INSIDE/SQLEXPRESS","sa","jordis99");
mssql_select_db("GunzDB");
$opened = 1;
if($opened == 0){
$pagetitle = "Server in maintenance";
}
?>