Ak dies, kas tev tur par perversijām kodā ;) Tik dīvaini tu tai ciklā tu tos datus meklē!
Vai nav labāk šādi:
<?php
error_reporting(E_ALL);
$login = $_POST['login'];
$password = $_POST['password'];
$pass = array_map('trim', file('../passwords.txt'));
$id = 0;
foreach($pass as $user) {
$id++;
$case = explode(':|:', $user);
if ($login == $case[0] && $password == $case[1]) {
$pass_hash = md5($password);
$cookie_data = "$userid:|:$pass_hash";
setcookie('stats_login', $cookie_data);
header('Location: main.php');
// tagad $id satur rindiņas numuru
}
}
die("Ievadītie dati nav pareizi!");
?>