boost :: archive_exception вызывает необработанное исключение в VisualStudio2012

boost::archive_exception смущает меня. Детали исключения следующие

Unhandled exception: boost::archive::archive_exception at memory location...

Это происходит при попытке следующего boost::serialization операция загрузки, которая по существу работает, когда BinarySearchTree<std::string> но не когда BinarySearchTree<int>

typedef boost::variant<BinarySearchTree<std::string>, BinarySearchTree<int>> BinarySearchTreeVariant;

BinarySearchTreeVariant search_tree_;

BinarySearchTree<std::string> string_search_tree_;
BinarySearchTree<int> int_search_tree_;

boost::shared_ptr<BinarySearchTree<std::string>> binary_string_search_tree_;
boost::shared_ptr<BinarySearchTree<int>> binary_int_search_tree_;

search_tree_ = int_search_tree_;

binary_int_search_tree_.reset(new BinarySearchTree<int>());

try{

if(!binary_int_search_tree_->load(binary_int_search_tree_, search_tree_name))
throw CustomException("Load of binary search tree to disk fail");

}
catch(CustomException &custom_exception){ }

Код, который определяет load как следует

bool load(boost::shared_ptr<BinarySearchTree> &tree, const std::string &search_tree_file_name)
{
// create and open an archive for output
std::ifstream reader(search_tree_file_name);

if(reader){
boost::archive::text_iarchive serial_reader(reader);
// read class state from archive
serial_reader >> *tree;    <<<--- Unhandled Exception
// archive and stream closed when destructors are called

}else if(reader.fail()){
reader.clear();
}

return true;
}

мой search tree определяется с boost::serialization следующее

class BinarySearchTree{

private:

class BinarySearchTreeNode{

public:

friend class BinarySearchTree;

private:

friend class boost::serialization::access;
template<class Archive>
void serialize(Archive &archive, const unsigned int /* file_version */){
archive & key;
archive & index;
archive & left;
archive & right;
}

T key;
long index;

boost::shared_ptr<BinarySearchTreeNode> left;
boost::shared_ptr<BinarySearchTreeNode> right;

};  // End Tree Node Class Definition

boost::shared_ptr<BinarySearchTreeNode> root;

friend class boost::serialization::access;
template <class Archive>
void serialize(Archive &archive, const unsigned int version){
archive & root;
}
};