diff --git a/addons/sale/sale.py b/addons/sale/sale.py
index 29826e1c293..66d7c1ac56a 100644
--- a/addons/sale/sale.py
+++ b/addons/sale/sale.py
@@ -1053,11 +1053,14 @@ class sale_order_line(osv.osv):
             q = product_uom_obj._compute_qty(cr, uid, uom, pack.qty, default_uom)
 #            qty = qty - qty % q + q
             if qty and (q and not (qty % q) == 0):
-                ean = pack.ean
+                ean = pack.ean or _('(n/a)')
                 qty_pack = pack.qty
                 type_ul = pack.ul
-                warn_msg = _("You selected a quantity of %d Units.\nBut it's not compatible with the selected packaging.\nHere is a proposition of quantities according to the packaging: ") % (qty)
-                warn_msg = warn_msg + "\n\n" + _("EAN: ") + str(ean) + _(" Quantity: ") + str(qty_pack) + _(" Type of ul: ") + str(type_ul.name)
+                warn_msg = _("You selected a quantity of %d Units.\n"
+                            "But it's not compatible with the selected packaging.\n"
+                            "Here is a proposition of quantities according to the packaging:\n\n"
+                            "EAN: %s Quantity: %s Type of ul: %s") % \
+                                (qty, ean, qty_pack, type_ul.name)
                 warning = {
                     'title': _('Picking Information !'),
                     'message': warn_msg