Hello, if I only include (no instantiation) the header <boost/mpl/map.hpp> I get the following error: /opt/boost/include/boost-1_33_1/boost/mpl/map/aux_/iterator.hpp:45: error: template argument 1 is invalid /opt/boost/include/boost-1_33_1/boost/mpl/map/aux_/iterator.hpp:45: error: template argument 1 is invalid /opt/boost/include/boost-1_33_1/boost/mpl/map/aux_/iterator.hpp:48: error: expected `{' before '>' token /opt/boost/include/boost-1_33_1/boost/mpl/map/aux_/iterator.hpp:48: error: expected unqualified-id before '>' token /opt/boost/include/boost-1_33_1/boost/mpl/map/aux_/iterator.hpp:66: error: expected nested-name-specifier before 'item_by_order' /opt/boost/include/boost-1_33_1/boost/mpl/map/aux_/iterator.hpp:66: error: expected ';' before '<' token g++ -v: Using built-in specs. Target: i486-linux-gnu Configured with: ../src/configure -v --enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --program-suffix=-4.1 --enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr --with-tune=i686 --enable-checking=release i486-linux-gnu Thread model: posix gcc version 4.1.2 20060729 (prerelease) (Debian 4.1.1-10) Any suggestion? regards, Oliver