Autodesk has released its AutoCAD Civil 3D 2009 Update 2. This update may contain fixes for issues you have been experiencing and also contains all the fixes included in AutoCAD Civil 3D 2009 Update 1, AutoCAD 2009 Update 1, AutoCAD 2009 Update 2, and AutoCAD Map 3D 2009 Update 1.
The updates and fixes are too numerous to list here, but if you open the linked Read Me file, below, you can investigate the issues Autodesk has resolved with AutoCAD Civil 3D 2009, that may have been causing you problems. As recommended by Autodesk, you should also read the Read Me file to understand the installation and use of this update. Autodesk strongly recommends that you read this entire document before you apply the update to your AutoCAD Civil 3D 2009 product.
The two links, below, will take you to either the AutoCAD Civil 3D 2009 Update file for download or to the Read Me file, as noted. Please keep in mind that the AutoCAD Civil 3D 2009 Update is a very large file (c3d2009sp20.exe), at 82.956 MB.
AutoCAD Civil 3D 2009 update Links:
AutoCAD Civil 3D 2009 Update 2.1
I know there were problems with the above links and Update 2 disappeared into the nether world of the net, but the link for AutoCAD Civil 3D 2009 Update 2.1 should work for you.