With the Ar7000 did you turn the transmitter on. Assuming the receiver has previosly been bound to the transmitter then when you power the receiver on, no lights will show until the transmitter is turned on. You should of course always turn the transmitter on first, but when setting up you may have forgotten. Also, you did select the right model on your transmitter didn't you! Hope I am not teaching granny how to suck eggs, but sometimes we overlook the obvious.
Regards
quadrix