Error massage

Hi
I have creat the attched rule to sent massage to the users having current stock qty, who created the product in product type "User_Product". When i am adding a product to the cart, below error massage are showing. Would you pls fix the issue!

Notice: Trying to get property of non-object in commerce_stock_line_item_product_enabled() (line 453 of E:\xampp\htdocs\martplug\profiles\martplug\modules\contrib\commerce_stock\commerce_stock.module).