Its not the Reciever
all HK products have been tested and are Simply HDMI certafied, the problem is the cable box and DVD player.
for HDMI to work from a source like DVD or Cable box to a display it is reqiured to send a HD copy protection signal to the TV one time, when you turn on the display and Source.
But when you hook a source through a switch or relay like a reciever and/or HDMI switcher it need to send the HD copy protection signal once every second or so, and if this doesnt happen you will not see any picture, because the source think you are trying to record the HD signal.
you might see if there is any updates for you Box and DVD player, and if you need to replace any sources, try to get one that is simply HDMI certafied like the HK dvd player.
not a 100% sure this is the problem, but this is the most common one.