Im using the Latest Version 5.0a ,its downloadable from the ascom site
http://ascom-standards.org
Also while you are there download the driver for Autostar Controller Mount
"Meade LX200 Classic and Autostar I (combined telescope/focuser, 5.0.2)"
Install the Ascom Platform first and then the Driver for the Autostar. I think with XP there is no Problem but with vista there will be a problem where the Autostar Driver is installed. Might Have to research the web to check where it should be installed.
Cheers
Tim