That says ... The NativeProcess class and its capabilities are only available to AIR applications installed with a native installer (extended desktop profile applications).
What does that mean in context of my Adobe AIR installation, which was a simple Adobe point-and-click that did not appear to look like a "native installer" ?
you can now implement a standard windows installer (ie a native installer, rather than the AIR installer) when users install your AIR app. Not sure if there's an option to do this in flex/flash builder but it can be done via command line.
adt -package -storetype pkcs12 -keystore myCert.p12 -target native NativeProcessTest.exe NativeProcessTest-app.xml NativeProcessTest.swf NativeApps/Windows/bin/echoTestWindows icons
or try this handy packager: