I have experienced this as well and have sneaking suspicion about support for WindowsXP as I recently tried to reload my Hal, on a WindowsXP machine, from the trial pack on the site. Result was that the download proceeded so far and then I got a message about dependencies missing. The trial area states support for Windows7, but nothing about WindowsXP, could it be that support for WindowsXP has been withdrawn from Hal. I am sure that, like me, there are still those who use WindowsXP for their Hal.