Today Autodesk released AutoCAD® Civil 3D® 2009 Update 1, which corrects known bugs and issues. Use the following link to open the AutoCAD Civil 3D Update 1 service and support page, where you can download service pack 1 (c3d2009sp1.exe):

Download AutoCAD® Civil 3D® 2009 Update 1

AutoCAD Civil 3D 2009 Update 1 page

Readme file for AutoCAD® Civil 3D® 2009 Update 1

The Readme contains information regarding the installation and use of this update Download AutoCAD® Civil 3D® 2009 Update 1:

AutoCAD Civil 3D Readme File