Problem linking boost::threads using MSVC6 SP4

I've created a windows console project with VC++ 6.0 and just used one of the examples in the documentation. I've also added the BOOST_HAS_THREADS macro in the settings. The program compiles well in debug mode but gives the following linking errors: Compiling... main.cpp Linking... msvcprtd.lib(MSVCP60D.dll) : error LNK2005: "public: virtual __thiscall std::runtime_error::~runtime_error(void)" (?? 1runtime_error@std@@UAE@XZ) already defined in main.obj msvcprtd.lib(MSVCP60D.dll) : error LNK2005: "public: __thiscall std::runtime_error::runtime_error(class runtime_error::runtime_error const &)" (??0runtime_error@std@@QAE@ABV01@@Z) already defined in main.obj msvcprtd.lib(MSVCP60D.dll) : error LNK2005: "public: __thiscall std::basic_string::~basic_string(void)" (??1? $basic_strin g@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QAE@XZ) already defined in main.obj msvcprtd.lib(MSVCP60D.dll) : error LNK2005: "public: __thiscall std::runtime_error::runtime_error(class runtime_error::basic_string const &)" (??0runtime_error@std@@QAE@ABV? $basic_strin g@DU?$char_traits@D@std@@V?$allocator@D@2@@1@@Z) already defined in libcpmtd.lib(ios.obj) msvcprtd.lib(MSVCP60D.dll) : error LNK2005: "public: __thiscall std::basic_string::basic_string(char const *,class basic_ string

::allocator<char> const &)" (??0?$basic_string@DU? $char_traits@D@std@@V?$allocator@D@2@@std@@QAE@PBDABV? $allocator@D@1@@Z) already defined in main.obj LINK : warning LNK4098: defaultlib "MSVCRTD" conflicts with use of other libs; use /NODEFAULTLIB:library Debug/threads.exe : fatal error LNK1169: one or more multiply defined symbols found Error executing link.exe.

Any help on this would be appreciated. Gunnar Olerud