Hello Jean-Noël, maybe you can try using the proposed patch at http://lists.boost.org/Archives/boost/2006/02/101539.php and report your results. I've got the hunch your problem might be related to the issue dealt with at that post. At this url, I have found two hpp files. I replaced the ones that originally came with the Boost 1.3.1 distribution with these ones. I still have an error, at the same line, however it is: C:/Boost/include/boost-1_33_1/boost/archive/detail/iserializer.hpp:115: error: no type named `type' in `struct boost::serialization::type_info_implementation > >' C:/Boost/include/boost-1_33_1/boost/archive/detail/iserializer.hpp:115: error: `get_instance' is not a member of `<declaration error>' While it was: C:/Boost/include/boost-1_33_1/boost/archive/detail/iserializer.hpp:115: error: incomplete type `boost::serialization::extended_type_info_null > >' used in nested name specifier with the original code from Boost 1.33.1. So this patch effectively changed something, but it still not working. I've not read the entire thread at your url since I did not understand it (it was about a specific compiler issue ??). Any ideas? Jean-Noël