regex and tokenizer, something wrong with namspace ?

Hi, I am a new user of the boost library (Actually with VC6 SP5 and stlport 4.0). Everything goes well when I use tokenizer and regexp in separated programs. But when I want to use the regex and the tokenizer library together I can not compile. for example, if I take the $(BOOST_ROOT)/libs/tokenizer/examples.cpp from John R. Bandela and just add the include line: #include the compiler gives me this error: Compiling... examples.cpp c:\program files\microsoft visual studio\vc98 \include\boost\token_functions.hpp(264) : error C2668: 'ispunct' : ambiguous call to overloaded function c:\program files\microsoft visual studio\vc98 \include\boost\token_functions.hpp(257) : while compiling class- template member function 'bool __thiscall boost::char_delimiters_separator

::is_ret(char) const' Error executing cl.exe.

examples.exe - 1 error(s), 0 warning(s) any idees ? Alexandre