Monster Power Center question


I just got the Monster Power Center HTS 3600. It has two LEDS, 'wiring OK' and 'ground OK' that do not come on. The manual says to unplug and call electrition. I tested the unit on every grounded outlet in my house. Samething. I have been using it, seems just fine. I just wonder what was going on here. Anyone know electricity?
alburger