please look at the attached DLL. I believe somewhere in there is should be looking for a dongle to be attached via usb. All i know is that the usb dongle serial is 89900000000B4.
If i have the dongle unplugged it returns the error if it being unplugged, plugged in its ok.
you can find the full app in the zip.
The program runs in xp on a virtual machine aswell. if you need to teamview to see it working in person then let me know and we can arrange something.