This is just a guess, since I don't have an Aether and am only going by the pictures...
The LED chain has all 6 LEDs of a color wired in series, with a sinking driver. This LED is the one at the supply end of the chain. According to the pinout of the LEDs, the tab is directly connected to the anode of the red LED. In circuits using the STCS05ADR driver, the anode of the LED strings is connected to the positive rail. The heatsink region on the board is grounded (hence the use of non-electrically-conductive epoxy for mounting the LED).
It sounds like there is a short somewhere on the board between the positive supply rail and ground. I would check both sides of the board; pay attention around the bridge rectifier, electrolytic caps, diodes by the constant-current sink chips, and regulators as that's the most likely place to find such a short.
/mike