I am posting this from over at the old site, for a user who needed the info pertaining to Civil 3D 2009.

Attempting to export a Shape File results in a CTD.  This error has been advertised, and the fix is available, as follows:

Copy the file from the following path:

(XP) -> C:\Documents and Settings\All Users\Application Data\Autodesk\AutoCAD Civil 3D 2009\R17.2\MapExport.ini
(VISTA) ->C:\ProgramData\Autodesk\AutoCAD Civil 3D 2009\R17.2\MapExport.ini

and paste it to:

(xp) -> C:\Documents and Settings\All Users\Application Data\AutodeskC3D 2009
(VISTA) -> C:\ProgramData\Autodesk\C3D 2009

If the command has been run, then a file will already exist.  OVERWRITE IT.

This should be fixed in Civil 3D 2010 and 2011.