Autocad Civil 3d 2013 64 Bit _VERIFIED_ Free 13
All the dll files in the Bin folder you extracted from the fdo-win64-3.7.0_4308.tar file, need to be copied to the FDO folder for civil 3d 2013. It is located here C:\Program Files\Autodesk\AutoCAD Civil 3D 2013\bin\FDO on my machine, which is a 64 bit machine. It should be similar to yours. If not, it will be located under you civil 3d install directory.
autocad civil 3d 2013 64 bit free 13