Website Register Errors

[warkey]

When i use any Register Page on me Xampp server i get MySQL Errors Like:

Warning: mssql_connect() [

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]: Unable to connect to server: WARKEYPC\SQLEXPRESS in C:\xampp\htdocs\config.php on line 9

And

Warning: mssql_select_db() [

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]: Unable to connect to server: (null) in C:\xampp\htdocs\config.php on line 10

And


Warning: mssql_select_db() [

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]: A link to the server could not be established in C:\xampp\htdocs\config.php on line 10

And all the settings are correct..
Im using no password, or something:

<?
$Title = 'TEST'; // Website title
$Title2 = 'Full items, premiums for free and all modes'; // Second part of the title.
$DBHost = 'WARKEYPC\SQLEXPRESS'; //The host of your DB (I.E: MACHINE\SQL2005)
$DBUser = ''; //Your DB User
$DBPass = ''; //Your DB Password
$DB = 'GunzDB'; //Your GunZ DB

$conn = mssql_connect($DBHost, $DBUser, $DBPass); // DONT CHANGE THIS //
mssql_select_db($DB); // DONT CHANGE THIS //
?>

Greetz Warkey