So unfortunately, this is an uncommon issue, so I don't have any specific troubleshooting steps for you. The nature of the device is that it operates on the 5.2/5.8 GHz frequencies and has a range of 33 ft. So for the initial setup, if they're separated by much distance, you could try putting them right next to each other. Also, you could try attaching the toroidal ferrite core to its power cord to reduce the EM interference.
Let me know the results either way.
Crystal Surround Airtrack HW - E551
I follow the instructions in the booklet (Press the IDSet on the sub for 5 seconds (though its closer to 10 before the link led starts flashing), then press SAT Mute on the remote for 5 seconds (though again its closer to 10 before I get the "ID SET" message on the bar). Then press the power button on the remote). I get a "HELLO" message followed by "D-IN" followed by a "CHECK SUBWOOFER" scrolling message for a few minutes before it turns off.
I've tried this with the tv and cable box connected, without either connected, used different hdmi slots on both the tv and sub with the same result each time.