Christophe - I'm trying to compile SimpleWithFunctors.cpp or SimpleTutorialEuml.cpp with VC8. Using the original review source code package (not the new eUML syntax). I have the same errors when compiling each: d:\boost\boost_1_41_0\boost/msm/front/euml/common.hpp(1305) : error C2953: 'boost::msm::front::euml::Process2_<ToProcessEvt,Value,Param1,Param2,Param3,`global namespace'::boost::disable_if<`global namespace'::boost::mpl::or_<`global namespace'::boost::is_same<Param2,void>::type,`global namespace'::boost::mpl::not_<`global namespace'::boost::is_same<Param4,void>::type>::type>::type>::type>' : class template has already been defined d:\boost\boost_1_41_0\boost/msm/front/euml/common.hpp(1243) : see declaration of 'boost::msm::front::euml::Process2_<ToProcessEvt,Value,Param1,Param2,Param3,`global namespace'::boost::disable_if<`global namespace'::boost::mpl::or_<`global namespace'::boost::is_same<Param2,void>::type,`global namespace'::boost::mpl::not_<`global namespace'::boost::is_same<Param4,void>::type>::type>::type>::type>' d:\boost\boost_1_41_0\boost/msm/front/euml/common.hpp(1342) : error C2953: 'boost::msm::front::euml::Process2_<ToProcessEvt,Value,Param1,Param2,Param3,`global namespace'::boost::disable_if<`global namespace'::boost::mpl::or_<`global namespace'::boost::is_same<Param2,void>::type,`global namespace'::boost::mpl::not_<`global namespace'::boost::is_same<Param4,void>::type>::type>::type>::type>' : class template has already been defined d:\boost\boost_1_41_0\boost/msm/front/euml/common.hpp(1243) : see declaration of 'boost::msm::front::euml::Process2_<ToProcessEvt,Value,Param1,Param2,Param3,`global namespace'::boost::disable_if<`global namespace'::boost::mpl::or_<`global namespace'::boost::is_same<Param2,void>::type,`global namespace'::boost::mpl::not_<`global namespace'::boost::is_same<Param4,void>::type>::type>::type>::type>' Something that I'm doing? I'll be trying on gcc soon. Thank you - michael -- ---------------------------------- Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com