Try this see if it works:
DoCmd.RunSQL "INSERT INTO T_Order_line (Description,ProductID) VALUES('" & Me.Description1 & "'," & Me.ProductID1 & ");"
Try this see if it works:
DoCmd.RunSQL "INSERT INTO T_Order_line (Description,ProductID) VALUES('" & Me.Description1 & "'," & Me.ProductID1 & ");"