RESOLVED : userpoints error

-- url of the page with the problem -- : sushi-cours.lu
-- HikaShop version -- : HikaShop Business 2.2.1
-- Joomla version -- : Joomla! 3.1.1 Stable [ Ember ] 26-April-2013 14:00 GMT
-- PHP version -- : 5.3.16
-- Browser(s) name and version -- : firefox 23.0.1
-- Error-message(debug-mod must be tuned on) -- : Hi,

i finished an order on my this by user a coupon, the amount of the order=0 -> that's ok, but when i click then to FINISH THE ORDER , the order is registered BUT here is the message i get :

Warning: Invalid argument supplied for foreach() in /........./plugins/hikashop/userpoints/userpoints.php on line 437

what can i do?