To use CivilCAD 2008 with AutoCAD 2010 on a 64-bit system, you need to address the compatibility gap between the older 32-bit plugin and the newer 64-bit CAD environment. While the 2008 version of CivilCAD was built for 32-bit systems, it is possible to bridge this gap with specific steps.
If you don’t have that upgrade, consider: civilcad 2008 para autocad 2010 64 bits better
to ensure registry keys and shared libraries are properly registered. Alternative Tools To use CivilCAD 2008 with AutoCAD 2010 on