[SOLVED] ShopX Session troubles

[!ShopXCart? &checkout=`4029` &debug=`GET` !]

<?php
// ShopXSession - plugin for MODx 0.9.x ShopX
// released to the Public Domain - use as you like.
// sets SESSION variables from the POST or GET as submitted
// by the various forms of shopX
// To Do: validate the input!

// System Events - OnWebPageInit

$e = &$modx->Event;

switch ($e->name) {

    case "OnWebPageInit":
        setPlaceholder('sessionDebug', 'In the ShopXSession plugin.');
        
        $_GET['sdebug'] = 'In the ShopXSession plugin.'); 
        
        // clear the cart
        if (isset($_GET['a']) && $_GET['a'] == 'clear') {
          unset($_SESSION['taxable']);
          unset($_SESSION['orders']);
          unset($_SESSION['order']);
          unset($_SESSION['tokens']);
          $modx->sendRedirect($modx->makeURL($modx->documentIdentifier));
        }
        
        
        // check for refresh or back button with token array
          $token = is_numeric($_POST['token'])?$_POST['token']:'';
        if (sizeof($_SESSION['tokens']) == 0 || !in_array($token, $_SESSION['tokens'], true)) {
            
            // get the Add to Cart values
            if(isset($_POST['add'])) {
              $itemid = $_POST['itemid'];
              $name = $_POST['name'];
              $quantity = $_POST['quantity'];
              $price = ereg_replace("[^0-9.]","",$_POST['shopItemPrice']);
              // add any custom values for each item here
        
              // add up quantities if repeat addition
              if(is_array($_SESSION['orders'][$itemid])) {
                $quantity += $_SESSION['orders'][$itemid]['quantity'];
              }
              // create an array of valid POST values
              $line = array(
              "itemid"=>$itemid,
              "name"=>$name,
              "quantity"=>$quantity,
              "price"=>$price,
              // add any custom values for each item here
              );
              
              // load values into the session
              $_SESSION['orders'][$itemid] = $line;
              // add to non-repeating token array
              $_SESSION['tokens'][] = $token;
          }
        
          // adjust SESSION values if checkout cart is modifed
          if(isset($_POST['scEditCart'])) {
            foreach($_POST['scItemQuantity'] as $key=>$value) {
              if($value == 0) { 
                unset($_SESSION['orders'][$key]);
              } else {
                $_SESSION['orders'][$key]['quantity'] = $value;
              }
            }
          } 
        } // end if not repeating token
        
        // load the tax values
        if(!isset($_SESSION['taxable'])) {
          $modx->runSnippet('ShopXTax');
        }
        
        // get the Shipping values - customize here if necessary to match a shipping option
        if(isset($_POST['shipping'])){
          $shipmethod = $_POST['shipmethod'];
          $values = explode('||',$_POST[$shipmethod]);
          $_SESSION['order']['shipmethod'] = $shipmethod;
          $_SESSION['order']['calcmethod'] = $values[0];
          $_SESSION['order']['calcamount'] = $values[1];
        }
        
        // get the payment option
        if(isset($_POST['paychoice'])) {
          $paymethod = $_POST['paymethod'];
          $_SESSION['order']['paymethod'] = $paymethod;
        }
        
        // load user data from payment modules 
        // include external php file, using conditionals to determine which module to load
        // for example, to get user data for ECHO credit card processing
        //if($_SESSION['order']['paymethod'] == 'echo' && isset($_POST['some_value)) {
        //include "assets/snippets/ShopX/payments/echo.php";
        //}
        exit;
    break;
    default:
        return;
}
?>