Vista - XBox 360 Media Center extender

Hi i'm Maurizio from Italy, i have a Xbox 360 sw updated that with a PC Vista
Ultimate sw updated don't work... i have connected through crossing lan cable
the network adapters, i've set my one live care for connection with xbox 360
extender (i have try without firewall too), i have shared with WMP 11 the
media dirctory with xbox 360, than restarting my xbox and pressing
mediacenter button into xbox menu find the 8 digit code that i put in vista
mediacenter configuration, at this point Vista find a new Hw, "XBox 360 Media
Center extender" and begin to install device but don't find any drver (windws
update and vista ultimate dvd). The configuration of vista media center stop
(into xbox screen said that Windows Mediacenter is configuring....) and i
can't continue. Someone can help me? Thanks bye