Make sure the HDSTB is connected to the HDTV via either component or HDMI and look at what input you are plugged into, many HDTV have multiples of each.
Apparently the DVR system will utilize a run-of-the-mill Motorola QIP6416 (dual HD-tuners and a 160GB hard drive) as the "hub" and a Motorola QIP2500 (basic STB that can receive content from the hub), both of which will communicate via MoCA (Multimedia over Coax Alliance) technology.