If you have the correct installer ( CivilCAD para AutoCAD 2010-2011 64 Bits ), follow these steps:

exists as a specific software package that bridges the 32-bit to 64-bit transition period in CAD software history. While it can be made to work—through careful installation, compatibility settings, and sometimes creative workarounds involving AutoCAD Civil 3D—the solution is not ideal for long-term professional use.