boost-1.42.0 uses invalid c++ code and gcc 4.5(with -std=c++0x) don't like it. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43915 https://svn.boost.org/trac/boost/ticket/3844
boost-1.50 should be -std=c++0x compatible as far as I know and since gcc-4.5 has incomplete C++11 support we're not going to fix that in boost-1.42.0