attempt to concatenate field 'value' (a function value)

Can anybody explain this for me? It used to work on an older system with
lua5.1.

i'm now using lua5.2, luabind version us 0.9.1 (on both systems)

g++ -o lua lua.cpp -lluabind -llua5.2 -ldl -I /usr/include/lua5.2
./lua
lua runtime error
[string "function test(t)..."]:2: attempt to concatenate field 'value' (a
function value)

extern "C" {
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
}

#include <luabind/luabind.hpp>
#include <iostream>

struct Test
{
  Test(int v) : value(v) {};
  ~Test() {};
  int value;
};


int DebuggerFunc(lua_State* L)
{
	luabind::object error_msg(luabind::from_stack(L, -1));
	std::cerr << error_msg << std::endl;
	return 0;
}

int main() {
  lua_State *L = luaL_newstate();
  luabind::open(L);

  luabind::module(L)
  [
    luabind::class_<Test>("Test")
    .def(luabind::constructor<int>())
    .def_readonly("value",&Test::value)
  ];

  luaL_dostring(
    L,
    "function test(t)\n"
    "  print(\"value : \" .. t.value)\n"
    "end\n"
  );

  Test t(4);

  try {
    luabind::call_function<int>(L, "test", &t);
  }
  catch (const luabind::error &er)
  {
    std::cerr << er.what() << std::endl;
    lua_State* Ler=er.state();
    DebuggerFunc(Ler);
  }
  catch (...)
  {
    std::cerr << "Unknown error!" << std::endl;
  }
  lua_close(L);
}


------------------------------------------------------------------------------