Softice: hwnd -> invalid window handle

hello, every one:

I find a very strange thing. the "hwnd" command always told me the parameter handle is the invalid window handle . and if the "idle" thread is the active thread, when I popup the softice, the "hwnd" command will told you it can't find the desktop. ok this can be fixed by the "addr" command. active another proccess by it. then you can list the windows list. but I can't resolve the first trouble , anyone know the way for it. please tell me...... SOS........

[OS] is the win2000