Hi, I tried defining: #define BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS #define BOOST_MPL_LIMIT_VECTOR_SIZE 30 // or whatever you need #define BOOST_MPL_LIMIT_MAP_SIZE 30 // or whatever you need /// Boost-MSM Includes // back-end #include "boost/mpl/vector/vector30.hpp" #include <boost/msm/back/state_machine.hpp> //front-end #include <boost/msm/front/state_machine_def.hpp> #include <boost/msm/front/functor_row.hpp> #include <boost/any.hpp> // for And_ operator #include <boost/msm/front/euml/operator.hpp> And i still get the following errors: builder1: In file included from /usr/local/include/boost/mpl/erase.hpp:19, builder1: from /usr/local/include/boost/fusion/mpl/erase.hpp:10, builder1: from /usr/local/include/boost/fusion/mpl.hpp:20, builder1: from /usr/local/include/boost/fusion/include/mpl.hpp:11, builder1: from /usr/local/include/boost/msm/back/state_machine.hpp:30, builder1: from File_Meta_FSM.h:18, builder1: from Open_Files_Mng.h:5, builder1: from Open_Files_Mng.cpp:1: builder1: /usr/local/include/boost/mpl/aux_/erase_impl.hpp:56: error: ‘_’ was not declared in this scope builder1: /usr/local/include/boost/mpl/aux_/erase_impl.hpp:56: error: ‘_’ was not declared in this scope builder1: /usr/local/include/boost/mpl/aux_/erase_impl.hpp:56: error: template argument 1 is invalid builder1: /usr/local/include/boost/mpl/aux_/erase_impl.hpp:56: error: template argument 2 is invalid builder1: /usr/local/include/boost/mpl/aux_/erase_impl.hpp:57: error: template argument 3 is invalid builder1: /usr/local/include/boost/mpl/aux_/erase_impl.hpp:62: error: ‘_’ was not declared in this scope builder1: /usr/local/include/boost/mpl/aux_/erase_impl.hpp:62: error: ‘_’ was not declared in this scope builder1: /usr/local/include/boost/mpl/aux_/erase_impl.hpp:62: error: template argument 1 is invalid builder1: /usr/local/include/boost/mpl/aux_/erase_impl.hpp:62: error: template argument 2 is invalid builder1: /usr/local/include/boost/mpl/aux_/erase_impl.hpp:63: error: template argument 3 is invalid and more of the same errors.. -- Kind regards, Yechiel Levi