LNK2005 occurs on Boost with VC7.1

On compiling test.exe as release module, many errors like the following occur:

error LNK2005: "struct check_is_small_t::boost::check_is_small_t boost::test_tools::`anonymous namespace'::check_is_small"

These erors are not occur as debug mode.

I found the information on problem of Boost with VC7.1, here(Boost-users ML)

I followed the information. When I turned pre-compiled header option off, the errors are cleared.