what can i do to make the email input echo, why won't this work


PHP Code:
<?php require_once('includes/html/header.php');?> 
            <div class="signup_strip"> 
                <div class="left_seller1"> 
                  <?php if ($_SESSION['is_user_name_exists'] == 1):?> 
                    <div class="error" style="color:red;">User Name Already Exists!</div> 
                  <?php endif;?> 
                  <?php if($_SESSION['is_user_email_exists'] == 1):?> 
                    <div class="error" style="color: red;">User Email Already Exists!</div> 
                  <?php endif;?> 
                  <form method="post" action="seller_signup_continue.php">` <p> 
                           <span class="left_signup_span">Email Address</span> 
                        <span class="right_signup_span"><input type="text" value="<?php     $_REQUEST['email']?>" name="email" class="sign_up_seller_field" /></span> 
                                <span><input type="submit" name="btnSub" value="Next"     class="nex_step_signup" /></span> 

PHP Code:
$_POST['password'] != $_POST['password_conf']) { 
$_SESSION['signup_password_error'] = true
header('Location: signup_seller.php'); 
        else { 
/* Start session and load library. */ $_SESSION['user_info'] = $_POST;        
error_reporting(E_ALL); `include 'seller_signup_continue_view.php'; 


PHP Code:
 <?php   $address $_SESSION['user_info']['email']; echo $address;  ?>
it give me the error: Notice: Undefined index: email

I have shorted the unnecessary parts of the pages and left the main parts, anyone able to help me i want it to echo the email they inputted, on on seller_signup_continue.php.