function remove() {
    global $messageStack;
    // cannot remove EC if DP installed:
    if (defined('MODULE_PAYMENT_PAYPALDP_STATUS')) {
      // this language text is hard-coded in english since Website Payments Pro is not yet available in any countries that speak any other language at this time.
      $messageStack->add_session('<strong>Sorry, you must remove PayPal Payments Pro (paypaldp) first.</strong> PayPal Payments Pro (Website Payments Pro) requires that you offer Express Checkout to your customers.<br /><a href="' . zen_href_link('modules.php?set=payment&module=paypaldp', '', 'NONSSL') . '">Click here to edit or remove your PayPal Payments Pro module.</a>' , 'error');
      zen_redirect(zen_href_link(FILENAME_MODULES, 'set=payment&module=paypalwpp', 'NONSSL'));
      return 'failed';
    }

    global $db;
    $db->Execute("delete from " . TABLE_CONFIGURATION . " where configuration_key LIKE 'MODULE\_PAYMENT\_PAYPALWPP\_%' or configuration_key like 'MODULE\_PAYMENT\_PAYPALEC\_%'");
    $this->notify('NOTIFY_PAYMENT_PAYPALWPP_UNINSTALLED');
  }