Have you installed the software? Poseidon needs to be installed but after that, I've found that you may need to run some additional commands:
Try this and see if it jump starts it. Open a shell and type
addusbhardware devs:usbhardware/subwayusb.device 0
addusbclasses
After a moment (if something is plugged in), or after you plug something in, you should see a bunch of annoying dialogs popup that indicate you've plugged in some USB devices. Things should work.
If this solves the issue for you, you can add those lines to the bottom of your S:User-Startup file.
