There's not much written about this on the web apparently so here is the solution to this error if you reuse your ESA on rebuilt shocks. There is a min and max sensor covering the 10mm preload range. If the technician moves the motor there is a chance that the motor gets "parked" beyond the min sensor so that when the motor starts to move, it can't find the end sensor and stops immediately with the subject error message.
The solution is to put 12 volts on the red/black two wire lead directly to the ESA motor so that it will move to its midrange. Stop the motor before it runs to the end and reverse polarity in case it does to center the motor. Again, there is only 10mm of full travel and the motor turns slowly.
Then run calibration with your GS911 which will run the full range and report min of 0 and max over 900+ in my case with an 09 RT.
EPM, the suspension dealer told me to install the shock and have codes read by the BMW dealer saying that the GS911 "reads codes differently" than their diagnostic. Do this instead. The GS911 is a great tool.