I installed boost_1_31_0 on Red Hat Fedora Core 1 with no apparent errors. I can compile and run the examples in /usr/local/src/boost_1_31_0/libs/date_time/example and I have compiled and run some graph examples so I think it is installed OK. However when I compile /usr/local/src/boost_1_31_0/libs/regex/example/snippets/credit_card_example.cpp (or anything that uses regex_replace) I get the following error: [root@athlon snippets]# g++ credit_card_example.cpp credit_card_example.cpp: In function `std::string machine_readable_card_number(const std::string&)': credit_card_example.cpp:35: error: `regex_replace' undeclared in namespace ` boost' credit_card_example.cpp: In function `std::string human_readable_card_number(const std::string&)': credit_card_example.cpp:40: error: `regex_replace' undeclared in namespace ` boost' TIA Scott