$ _SESSION未在php中检索

I'm using this captcha plugin, http://code.google.com/p/cool-php-captcha/ in my website, I'm having the HTML form in my wamp server, and it is submitting it to my live sever located in http://www.example.com/experiments/emaileasy/index.php. Now the problem is, the session return empty array and it is not retrieving when i submit the form in $.ajax, but i can able to see the value if i directly visit the url in my browser. I hardly don't know how to proceed with this,

Here is my index.php file where i'm submitting the form,

<?php
    session_start();

    print_r($_SESSION);die;

    if(isset($_POST))
    {
        if (empty($_SESSION['captcha']) || trim(strtolower($_POST['captcha'])) != $_SESSION['captcha']) 
        {
            header("HTTP/1.0 400 Bad Request");
            header('Content-type: application/json');
            die(json_encode(array('message' => 'Please recheck the captcha')));
        }

        try {
            $conn = mysql_connect('localhost', 'root', '');
            mysql_select_db('expo', $conn);
            $status = mysql_query("INSERT INTO table SET content = '".mysql_real_escape_string($_POST['content'])."'");

            header("HTTP/1.1 200 OK");
            header('Content-type: application/json');
            echo json_encode(array('message' => 'Success!'));
        } catch (Exception $e) {
            header("HTTP/1.0 400 Bad Request");
            header('Content-type: application/json');
            echo json_encode(array('message' => 'Failed'));
        }
    }
?>

Here is my JS file,

$( "#Form" ).submit(function( event ) {
  // Stop form from submitting normally
  event.preventDefault();

  var data = "content="+$( "#content" ).val()+"&captcha="+$( "#captcha" ).val();
  $.ajax({
      type: "POST",
      url: baseurl+'experiments/emaileasy/index.php',
      data: data
  });
});

If i'm submitting the form to localhost it is working properly, but when i submitting it to live server, the session returns empty array.

Here is my .htaccess file,

<IfModule mod_headers.c>
    Header set Access-Control-Allow-Origin "*"
    Header set Access-Control-Allow-Headers X-Requested-With
</IfModule>

Please note that, the session is set through cool-php-captcha which lies on the server. And one more thing i noted is, when the captcha is loaded a session file is getting created and when i post the values a new session file is created in the name of PHPSESSID passing in AJAX requests(I noted this through Firebug response headers).

I'm getting the $_POST values also, but session return empty array when retrieve through AJAX. Please help. Thanks in advance.