Receiving Error- Error: user account already exists..

I keep receiving the following error..( Error: user account already exists..
) although I don't have any data in my table. Any help would be appreciated.

The code follows:

 

 

<?php 

session_start();

 

 

include ('dbc.php'); 

 

 

 

if (isset($_POST['Submit']) =='Register')

{

   if (strlen($_POST['email']) < 5)

   {

    die ("Incorrect email. Please enter valid email address..");

    }

   if (strcmp(isset($_POST['pass1']),isset($_POST['pass2'])) ||
empty($_POST['pass1']) )

                { 

                //die ("Password does not match");

                die("ERROR: Password does not match or empty..");

 

                }

                if (strcmp(md5($_POST['user_code']),$_SESSION['ckey']))

                { 

                                                 die("Invalid code entered.
Please enter the correct code as shown in the Image");

                                } 

                $rs_duplicates = mysql_query("select id from users where
user_email='$_POST[email]'");

                $duplicates = mysql_num_rows($rs_duplicates);

                

                if ($duplicates> 0);

                {              

                //die ("ERROR: User account already exists.");

                header("Location: register.php?msg=ERROR: User account
already exists..");

                exit();

                }

                

                                

                                

                

                $md5pass = md5($_POST['pass2']);

                $activ_code = rand(1000,9999);

                $host  = $_SERVER['HTTP_HOST'];

                $uri   = rtrim(dirname($_SERVER['PHP_SELF']), '/\\');

                mysql_query("INSERT INTO users

 
(`user_email`,`user_pwd`,`country`,`joined`,`activation_code`,`full_name`)

                                                                  VALUES

 
('$_POST[email]','$md5pass','$_POST[country]',now(),'$activ_code','$_POST[fu
ll_name]')") or die(mysql_error());

                

                $message = 

"Thank you for registering an account with $server. Here are the login
details...\n\n

User Email: $_POST[email] \n

Password: $_POST[pass2] \n

Activation Code: $activ_code \n

____________________________________________

*** ACTIVATION LINK ***** \n

Activation Link:
http://$host$uri/activate.php?usr=$_POST[email]&code=$activ_code \n\n

_____________________________________________

Thank you. This is an automated response. PLEASE DO NOT REPLY.

";

 

                mail($_POST['email'] , "Login Activation", $message,

    "From: \"Auto-Response\" <notifications@$host>\r\n" .

     "X-Mailer: PHP/" . phpversion());

                unset($_SESSION['ckey']);

                

                echo ("Registration Successful! An activation code has been
sent to your email address with an activation link...");exit;

                }

?>