Problem s Přihlášením

<?
if($_COOKIE[pass]=="" && $_COOKIE[log]==""){
if($pass=="" or $log==""){
echo "
<center>
<form method='post'>
<table>
<tr><td><center><font size='2'>Login:</font><td></td></tr>
<tr><td><center><input type='text' name='log'><br></td></tr>
<tr><td><center><font size='2'>Heslo:</font></td></tr>
<tr><td><center><input type='password' name='pass'></td></tr>
<tr><td><center><input type='submit' value='Přihlásit'></td></tr>
</table>
</form>
";
}else{
include("include/connect.php");
$heslo_kod = sha1($pass);
$user_vyber = MySQL_Query("SELECT * FROM users WHERE login = '$log'");
while($user_db = MySQL_Fetch_Array($user_vyber)){
if($user_db['pass']=="$heslo_kod" && $user_db['login']=="$log"){
echo "Přihlašuji uživatele <br> <span style='color:red'>$user_db[login]</span>";
SetCookie ("pass", "$heslo_kod");
SetCookie ("login", "$log");
echo'<br><b>Vyčkejte prosím...</b><br><br>
<img src="img/up.gif"><br><br>
<meta http-equiv="refresh" content="1">';
}else{
echo "Spatny Login nebo Heslo";
};};};
}else{
//------------------------UZIVATELSKY PANEL----------------------------------------------
include("include/connect.php");
$user_vyber = MySQL_Query("SELECT * FROM users WHERE login = '$log'");
while ($user_db = MySQL_Fetch_Array($user_vyber)):
echo"
<h2><span style='color:red'>$user_db[login]</span></h2>
<a href='administrace_user.php?id=clanky'>Administrace</a><br>
<a href='profile.php?p_id=$user_db[id]'>Tvůj Profil</a><br>
<a href='index.php?p=logout'>Odhlásit</font></a>";
endwhile;
};
?>