Problem solved!! Thanks to all who replied. As it turns out, when I plugged the RioCar into the car sled, the unit worked perfectly!! However, when I plugged the RioCar back into the AC adapter, the "clicking/blinking failure" was reproduced -- thus, there is probably some problem with either my AC adapter or the circuit that utilizes power from the AC adapter. Special thanks to Deadfire who mentioned that he had a similar problem when his AC adapter failed -- otherwise, I probably wouldn't have thought to try the unit out in the car sled, and would have been very very unhappy.

So I'm thinking that the AC adapter is probably broken -- do you guys think that SonicBlue would send me another one? The adapter produces 12.1V without load, but I don't have time to see if it can produce adequate current under the load of the RioCar or if the voltage drops appreciably.

Valsalva