[hostar]

Where do you trying windows fastboot?
On physical computer or virtual computer?
When I was developing it, I used virtual computer, Windows XP.
It needs to run VirtualBox under root.

After your reply I restarted to Windows.
In fact, my Windows are somehow partially wrecked.
But what I found was this:

0) Note: I have Windows 7 x64
1) Fastboot didn't work at all in Safe Mode in Windows
2) In normal Windows mode fastboot needs installed libusb drivers
3) Fastboot worked after selected "Disable driver signing check" (or something like that, I don't have English Windows) in F8 menu on Windows boot
4) But it works even if I HAVEN'T disabled that checking, but is was in some mode with many services disabled, because I just can't run Windows normally now.
5) Behavior you described I encountered when drivers wasn't installed or fastboot dropped out.

Attaching fastboot, that write number of found busses and devices, if they are not zero.