Boost 1.4.0, "assert" identifier not found

Question

I'm trying to compile an old project that was originally written for linux on windows. It uses boost 1.4.0, and whenever I compile it throws error C3961: "assert" : identifier not found. I'm using Visual Studio 208 SP1 When I drill down into assert.hpp it includes this:

# include <assert.h> // .h to support old libraries w/o <cassert> - effect is the same
# define BOOST_ASSERT(expr) assert(expr)

BOOST_ASSERT is actually what's failing, and VS doesn't seem to recognize assert() even though assert.h is obviously included. As far as I can tell, all the fails are in files that are part of boost, not my own code, but it throws about 1200 of them.

Any ideas how to fix this?