The NCE 5 amp systems and the NCE CS02 command station were designed prior to the widespread use of sound equipped locomotives. The higher inrush of current on sound decoders causes the programming track to think that a short circuit is detected. To help eliminate this issue you can modify your command station with this article or add a programming track booster.
Soundtraxx PTB-100 http://www.soundtraxx.com/access/ptb100.php
*** note DO NOT connect a programming track booster of any kind to an NCE Power Cab. The programming track mode of the Powercab is a newer design that incorporates the ability to program sound equipped decoders.
Hook up the PTB-100 as follows:
The YELLOW wires connect to the programming track output on the right side of the command station.
The BLACK wires are for system power. The PTB-100 requires 12VAC or 14VDC 500mA. you can use the same power supply that runs your command station / booster PROVIDED that it meets these requirements. A better idea is to use a separate power supply
The ORANGE wires are your new programming track output that go to the programming track.