[boost] unordered_map failing to compile on MSVC7.1 using STLport

For some reason, I get the following compiler error on Visual Studio .NET 2003 when using STLport 5.2.1: boost\unordered\detail\allocator_helpers.hpp(318) : error C2039: 'select_on_container_copy_construction' : is not a member of 'stlpd_std::allocator<_Tp>' Any idea why this is happening? If not, what other information can I provide? --------- Robert Dailey