i tryed putting the code at the start of one of the pages and got the following error

Fatal error: Call to undefined function: getsqlvaluestring() in /usr/users1/jonfort/public_html/think/beta/index.php on line 23

the code is

GetSQLValueString($loginUsername, "text"), GetSQLValueString($password, "text"));

i placed this whole code at the top of the page

<?php

// *** Validate request to login to this site.

if (!isset($_SESSION)) {

  session_start();

}

$loginFormAction = $_SERVER['PHP_SELF'];

if (isset($_GET['accesscheck'])) {

  $_SESSION['PrevUrl'] = $_GET['accesscheck'];

}

if (isset($_POST['userid'])) {

  $loginUsername=$_POST['userid'];

  $password=$_POST['password'];

  $MM_fldUserAuthorization = "";

  $MM_redirectLoginSuccess = "php.php";

  $MM_redirectLoginFailed = "failed.php";

  $MM_redirecttoReferrer = false;

  mysql_select_db($database_hostprop, $hostprop);

  $LoginRS__query=sprintf("SELECT userid, password FROM think_signup WHERE userid=%s AND password=%s",

    GetSQLValueString($loginUsername, "text"), GetSQLValueString($password, "text"));

  $LoginRS = mysql_query($LoginRS__query, $hostprop) or die(mysql_error());

  $loginFoundUser = mysql_num_rows($LoginRS);

  if ($loginFoundUser) {

     $loginStrGroup = "";

          if (PHP_VERSION >= 5.1) {session_regenerate_id(true);} else {session_regenerate_id();}

    //declare two session variables and assign them

    $_SESSION['MM_Username'] = $loginUsername;

    $_SESSION['MM_UserGroup'] = $loginStrGroup;               

    if (isset($_SESSION['PrevUrl']) && false) {

      $MM_redirectLoginSuccess = $_SESSION['PrevUrl'];

    }

    header("Location: " . $MM_redirectLoginSuccess );

  }

  else {

    header("Location: ". $MM_redirectLoginFailed );

  }

}

?>

and it returned the error

GetSQLValueString($loginUsername, "text"), GetSQLValueString($password, "text"));

varchar as it is a name (text)

so what should i do about the missing code?