The problem with paying affiliate fees

-- url of the page with the problem -- : www.keks-store.ru
-- HikaShop version -- : 2.6.3
-- Joomla version -- : 3.5.1

Tell us how to set up the payment of remuneration to partners via paypal as well as in some other way. Because when I click on the pay button pops up an error (see screenshots).

Hi,

Well, that's just a warning. You can remove it by adding the line:
$order->history = new stdClass();
before the line:
$order->history->history_reason=JText::sprintf('ORDER_CREATED');
in the file admininistrator/components/com_hikashop/controllers/user.php

But that won't change anything with the payment. Normally, it should redirect you to PayPal on that page.
It's not the case ?
Nothing happens ? Do you have any javascript error in the console error of your browser on that page ?