[boost] link problem of boost.thread in vc7.1

I use VC7.1 to compile it into boost_thread-vc71-mt-gd-1_32.lib. But I cannot link it into a MFC applicatioin(_MDd code generation). I get the error like this:"error LNK2019: unresolved external symbol "__declspec(dllimport) public: void __thiscall boost::thread::join(void)" (__imp_?join@thread@boost@@QAEXXZ) referenced in function "public: virtual int __thiscall CserverApp::InitInstance(void)" (?InitInstance@CserverApp@@UAEHXZ)" Anyone can help me? Thank you:)