register probleem?

<?if ($_SERVER['REQUEST_METHOD'] == 'POST'){
  $checkuserQ = mysql_query("SELECT naam FROM users WHERE naam='". mysql_real_escape_string($_POST['naam']) ."'");


  if (mysql_num_rows($checkuserQ) > 0){
 echo("<script>alert(''.['naam'].' is al geregistreert.')</script>"); 
 die();
  }
  $checkemailQ = mysql_query("SELECT email FROM users WHERE email='". mysql_real_escape_string($_POST['email']) ."'");
  if (mysql_num_rows($checkemailQ) > 0){
 echo("<script>alert('Deze email is al geregistreert.')</script>"); 
 }
	if (!filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)) {  
    echo("<script>alert('Dit is geen correcte email, probeer het nog eens.')</script>"); 
	die();
}
  
 if (!$_POST['naam'] | !$_POST['email'] | !$_POST['achternaam'] | !$_POST['login'] | !$_POST['password'] | !$_POST['password2'] ) {
 		die("<script>alert('Oops, je bent een velt vergeten!')</script>");
 	}
 	if ($_POST['password'] != $_POST['password2']) {
 		echo ("<script>alert(U wachtwoorden waren niet het zelfden, probeer het nog is.')</script>");
 	die();
	}
	}
$query = "INSERT INTO users (naam, achternaam, login, email, password) VALUES ('". mysql_real_escape_string($_POST['naam']) ."', '". mysql_real_escape_string($_POST['achternaam']) ."', '". mysql_real_escape_string($_POST['login']) ."',, '". mysql_real_escape_string($_POST['email']) ."', , '". mysql_real_escape_string(md5($_POST['password'])) ."')";
mysql_query($query) or die (mysql_error());
echo "<script>alert('U bent geregistreert!')</script>";?>