PHP - Regisitry Form With Header Error.

Before asking, I have read this. http://www.phpfreaks.com/forums/index.php?topic=37442.0  I am just confused why my header still doesn't work. I don't think I'm outputting anything in the else statement where my header(Location: 'registerconf.php') is; Here's the code

Code: [Select]
<?php require('includes/header.php'); ?>
<?php
//VARIABLES
$submit = mysql_real_escape_string($_POST['submit']);
$username = mysql_real_escape_string($_POST['username']);
$user = $_POST['username'];
$firstname = mysql_real_escape_string($_POST['firstname']);
$lastname = mysql_real_escape_string($_POST['lastname']);
$email = mysql_real_escape_string($_POST['email']);
$password = mysql_real_escape_string($_POST['password']);
$passwordconf = mysql_real_escape_string($_POST['passconf']);
$ageconf = mysql_real_escape_string($_POST['ageconf']);
$tosconf = mysql_real_escape_string($_POST['tosconf']);

$loweruser = strtolower($username);

$checkuser = mysql_query("select * from users where username_lower='{$loweruser}'");
$userexists = mysql_fetch_assoc($checkuser);

$emailexistsquery = mysql_query("select * from users where email='{$email}'");
$emailexists = mysql_fetch_assoc($emailexistsquery);
    
/*CHECKS
 * Many checks need to be done, the checks will also be done in order. The order will 
 * be listed here
 * 
 */

if(isset($_POST['submit'])) {
    if(empty($username)||empty($firstname)||empty($lastname)||empty($email)||empty($password)||empty($passwordconf)){
        echo('Please fill out all fields!<br/>'); 
    }else{
        if($userexists) {
            echo "Username $username already exists";
    }else{
        if(strlen($username)>15||strlen($username)<5) {
            echo "Username must be between 5 and 15 characters";
        }else{
            if (!preg_match('/^[a-zA-Z0-9]+$/', $user)) {
                echo "Username can only contain letters and numbers with no spaces";
            }else{
               if(strlen($firstname)>20) {
                   echo "Your first name cannot be larger than 20 characters";
               }else{
                   if(!preg_match('/^[A-Z]{1}[a-z]+$/', $firstname)) {
                       echo "Your first name can only contain letters and must start with a capital followed by lowercase letters";
                   }else{
                       if(strlen($lastname)>20) {
                           echo "Your last name cannot be larger than 20 characters";
                       }else{
                         if(!preg_match('/^[A-Z]{1}[a-z]+$/', $lastname)) {
                           echo "Your last name can only contain letters and must start with a capital followed by lowercase letters";
                                    }else{
                                        if(strlen($email)>40) {
                                           echo "Email cannot be longer than 40 characters";                                                                               
                                    }else{
                                       if(!filter_var($email, FILTER_VALIDATE_EMAIL)) {
                                         echo "Invalid Email";
                                     }else{
                                         if($emailexists) {
                                             echo "Email already exists";
                                         }else{
                                            if(strlen($password)<5||strlen($password)>30) {
                                                echo "Password must be between 5 and 30 characters";                                            
                                            }else{
                                                if($password!=$passwordconf) {
                                                echo "Passwords don't match";
                                            }else{
                                                 if($ageconf=='') {
                                                     echo "You must be 16 or older to register";
                                                 }else{
                                                     if($tosconf==''){
                                                         echo "You must agree with the Terms of Service";
                                                     }else{
                                                         //add to database
                                                         $mdpass = md5($password);
                                                         $rand = rand('12345','54321');
                                                         $activekey = time()+$rand;
                                                         
                                                         $query = "insert into users set username='{$username}', username_lower='{$loweruser}', firstname='{$firstname}', lastname='{$lastname}', email='{$email}', activationcode='{$activekey}', password='{$mdpass}'";  
                                                         $query2 = mysql_query("select * from users where username='{$username}'");
                                                         
                                                         mysql_query($query);
                                                         
                                                         $sqluserid = mysql_fetch_assoc($query2);
                                                             
                                                         $userid = $sqluserid['id'];
                                                       
                                                         
                                                         $to = $email;
                                                         $subject = "Activate your account";
                                                         $message = "Welcome to Site! $firstname! </br>
                                                         Thank you for taking your time to register an account for the Site Networks your click the link below to activate your account! </br></br>
                                                         <a href=ns.com/registerconf.php?pid=$userid&activate=$activekey;
                                                         ";
                                                                                                       
                                                        
                                                         header('Location: registerconf.php');                                                         
                                                     }
                                                 }
                                            }     
                                       }
                             }                        
                          }
                          
                       }   
                   }
               }
            }
        }
     }
    }
   }
  }
  echo "";
}

echo "<table>
<form name='login' method ='POST' action='register.php'>
    <tr><h3>Register your account and get access to all of the Networks!<h3></tr>
    <tr><td>Username</td><td><input type='text' name='username' value=".$username."></td></tr>
    <tr><td>First Name</td><td><input type='text' name='firstname' value=".$firstname."></td></tr>
    <tr><td>Last Name</td><td><input type='text' name='lastname' value=".$lastname."></td></tr>
    <tr><td>Email</td><td><input type='text' name='email' value=".$email."></td></tr>
    <tr><td>Password</td><td><input type='password' name='password'></td></tr>
    <tr><td>Confirm Password</td><td><input type='password' name='passconf'></td></tr>
    <tr><td>I am 16 or older</td><td><input type='checkbox' name='ageconf'></td></tr> 
    <tr><td>I agree with the <a href='tos.php'>terms of service</a></td><td><input type='checkbox' name='tosconf'></td></tr> 
    <tr><td><input type='submit' name='submit' value='Register'>
</form>
</table>
";

?>
<?php require('includes/footer.php'); ?>

It might be the sql statement but I need that for the user id.
Thanks