Session local/web

Dobry vecer, mam problem s mym skriptem na prihlasovani. Na hostingu mi funguje
bez problemu, ale na localhost to vypisuje chyby:


Warning: session_start() [function.session-start]: Cannot send session cookie -
headers already sent by (output started at C:\wamp\www\login_do.php:1) in
C:\wamp\www\login_do.php on line 17

Warning: session_start() [function.session-start]: Cannot send session cache
limiter - headers already sent (output started at C:\wamp\www\login_do.php:1)
in C:\wamp\www\login_do.php on line 17

Warning: Cannot modify header information - headers already sent by (output
started at C:\wamp\www\login_do.php:1) in C:\wamp\www\login_do.php on line
28


login_do.php

<?php
include ("connect.php");
if (isset($_POST['user'])
and isset($_POST['pass']))

{

$sql = "SELECT id, jmeno, nick, heslo, status, " .
"FROM user " .
"WHERE nick='". $_POST['user']. "' " .
"AND heslo='". $_POST['pass']. "' ";
$vysledek = mysql_query($sql, $lin)
or die('Nelze vyhledat informace o uživateli; ' .
mysql_error());

if ($radek = mysql_fetch_array($vysledek)) {
session_start();
$_SESSION['id'] = $radek['id'];
$_SESSION['status'] = $radek['status'];
$_SESSION['jmeno'] = $radek['jmeno'];
$_SESSION['nick'] = $radek['nick'];
}
header( "Location:lol.php" );
}
else{
echo "Nemáte právo na vstup do tajné sekce!";
}
?>


Muzete mi nekdo poradit, kde je problem? Dekuju Dave

Diky moc, bylo to tim