My previous mail got truncated, the completed listing is below:

Hi,

I have the following piece of code that is generating the above assertion. Could someone tell me what is going wrong:

template <typename T>
struct my_node_t : public avl_set_base_hook<> {
  my_node_t(T data): m_data(data) {}

  template <typename U>
  friend  bool operator< (const my_node_t<U>& lhs, const my_node_t<U>& rhs) {
      return lhs.m_data < rhs.m_data;
  };

  T m_data;
};

typedef my_node_t<int> avlnode_t;
typedef avltree<avlnode_t> avltree_t;

struct args_t {
  unsigned int seed[MAX_THREADS];
  vector<avlnode_t>* items;
  avltree_t* tree_ptr;
  thread_args_t(size_t num_threads,
                avltree_t* map,
                vector<avlnode_t>* init_vec,
                size_t num_entries,
                unsigned int s)  {
    num_items = num_entries;
    tree_ptr = map;
    initial_items = init_vec;
    for (size_t i = 0; i < num_threads; ++i) {
      seed[i] = i + s;
    }

    for (int i = 0; i < 10; ++i) {
      initial_items->push_back(i * 100);
    }

    for (vector<avlnode_t>::iterator it = initial_items->begin(); it != initial_items->end(); ++it) {
      tree_ptr->insert_equal(*it);
    }
  }

  ~thread_args_t() {
    tree_ptr->clear();
    delete tree_ptr;
    delete initial_items;
  }
};

void worker(void* args_ptr) {
  args_t* args = static_cast<args_t*>(args_ptr);
  avltree_t* tree = args->tree_ptr;
  vector<avlnode_t>* values = args->initial_items;
  int index = 5; //generate_random<int>(my_seed, 0, num_items + 1)))
  avlnode_t& find_element = *(values->begin() + index);
  tree->insert_equal(find_element);
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ <-raises exception
}