I don't have a lot of experience on the specific alarm type, but I am an I.D.S alarm tech. usual this sleeping that you are talking about when arming occurs when there are zones(pir's) violated. if you installed it yourself, check that all your wires are connected properly on the mother board, if that fails, start checking the pir's. iI'm sure this is a loose wire on one of the pir's. the keypad should flash the faulty zones
DD, February 2009