This is a tricky one to debug. The "stopped working" message in Windows actually means "full-on crashed". The problem seems to be caused by trying to initialise a connection to the Kinect device, but that is actually a fairly straightforward part of the code, and is identical to the OpenNI samples which are apparently working. To check a quick few things that have come up in the past:

• Have you had any other Kinect software installed before (OpenKinect, or other versions of OpenNI?)
• Did you install OpenNI using the links on the Greenfoot website (installing direct from the OpenNI site could lead to you having a different version)

You can also try running the Kinect Server exe using the "-m" or "-n" flags (might be "/m" or "/n" on Windows, I don't have a Windows machine to hand right now). That would involve opening up a command prompt (or pressing Windows key + R) and running: "C:/Program Files/Greenfoot Kinect Server/Greenfoot-Kinect-Server.exe" -m -n (The m flag turns off some of the image processing, the n flag adjusts the networking. It's a bit of a long shot but might be worth trying.)

Because I originally could not get the drivers to load, I used alternative software versions from the official OpenNi sites, and this seems to have caused the issue, as I followed your suggestion and reinstalled the versions from the Greenfoot site and it now works. Thanks. I managed to solve the original driver problem by installing them manually through the "Add hardware" program in Control Panel. If I didn't do that, the drivers failed to automatically install and there was nothing in the Device Driver panel to show any Primesense devices. I'm suprised this hasn't been a problem for others.