First attempt to login is rejected but second attempt succeeds

I am currently having problems with my login - the first attempt to login is always rejected but the second attempt succeeds. Any idea how I can resolve this?

login.php

if(isset($_POST['pmsubmit']))
    {
    LoginSubmit('pm', 'pmname', 'pmpass');
    }

    if (isset($_POST['tssubmit'])) {
    LoginSubmit('ts', 'dept', 'tspass');
    }

function LoginSubmit($pm_or_ts, $the_name_input, $the_pass_input)
{
  global $pdo;
    $salt = "$2a$12ehTk6%^jswam)*usnyruhst";
  $posted_name = $_POST[$the_name_input];
    $posted_pass = crypt($_POST[$the_pass_input], $salt);   
  // check if password matches the one in the table
  $query = $pdo->prepare("SELECT * FROM db_pass WHERE pass = :pass");
  $query->execute(array(":pass" => $posted_pass));
  // if there is a match then we log in the user
  if ($query->rowCount() > 0)
  {
    // session stuff
    $_SESSION[$the_name] = $posted_name;
      $_SESSION['id'] = $row['id'];
    // refresh page
    header( 'Location: ' . $pm_or_ts . '/index.php' ) ;
    exit;
  } 
  // if there is no match then we present the user with an error
  else
  { 
    echo '
    <script>
    $(function() {
        $( "#dialog-message" ).dialog({
      modal: true,
      buttons: {
        Ok: function() {
          $( this ).dialog( "close" );
            }
        }
        });
    });
    </script>
        <div id="dialog-message" title="Incorrect password">
        The password you have provided is incorrect.<br>Please try again.
    </div>
    ';
  }
}
?>

pm/index.php

<?php 
session_start();
setcookie("pmw", $_SESSION[$thename], time()+7200, '/');
require_once("../resources/php/connection.php");

if (empty($_SESSION[$thename]) || empty($_COOKIE['pmw']) ) {
    header("Location: ../login.php");
    exit;
}
?>

ts/index.php

<?php 
session_start();
setcookie("ts", $_SESSION[$thename], time()+7200, '/');
require_once("../resources/php/connection.php");

if (empty($_SESSION[$thename]) || empty($_COOKIE['ts']) ) {
    header("Location: ../login.php");
    exit;
}
?>