The Autodesk Labs process is all about feedback and fast action. Yesterday we released the
technology preview. Though the technology preview is working correctly with AutoCAD Civil 3D 2011, users with update 1 of AutoCAD Civil 3D are experiencing crashes. I have removed the download link while the team addresses the problem. I will make the technology preview available again when I have posted a new installer that contains a correction for this issue.
Thanks to everyone who tried this technology preview on its first day. We apologize for the crashes. Most often we get these things right. This time we did not, but experimenting is indeed part of the Autodesk Labs experience.