Passing existing C++ objects to Lua and calling th

I'm working on a little simulation project which uses Lua to drive the behavior of individual units (ants) and using Luabind to glue the C++ and Lua sides together. Each individual ant (there are different types, derived from the base class Ant) has a Run() function, which calls the appropriate script; the script then carries out whatever actions need to be taken, calling the exposed class functions and possibly free functions. I've gotten the Run function (in C++) to successfully execute the matching Run function in the Lua script (which just prints some text at the moment).

void AntQueen::Run()
{
    lua->GetObject("QueenRun")(GetID());
}

lua is just a manager class which retrieves the function from the script. The above is calling the following in a Lua file:

function QueenRun(ID)
    print("The Queen is running!")
    print(ID)
end

And Luabind registration looks like this for the AntQueen class:

void Register(lua_State *luaState)
{
    using namespace luabind;
    module(luaState)
    [
        class_<AntQueen, Ant>("AntQueen")
        .def("Eat", &AntQueen::Eat)
        .def("ExtractLarvae", &AntQueen::ExtractLarvae)
        .def("GetMaxLarvaeProduced", &AntQueen::GetMaxLarvaeProduced)
        .def("GetNumAvailLarvae", &AntQueen::GetNumAvailLarvae)
    ];
}

The way it's set up now, ants are created, removed, and found through a simple factory/manager. Each ant can be retrieved by calling static Ant* AntFactory::GetAntByID(const int ID) which just finds the ant in a hash map and returns a pointer to the ant. What I'm trying to do is get Lua to be able to do something like the following:

function QueenRun(ID)
    ant = GetAntByID(ID)
    larvae = ant:GetNumAvailLarvae()
    print(larvae)
    ant:Eat()
end

The above is just a made up example, but hopefully it shows what I'm trying to achieve. I don't want Lua to garbage collect the objects, because they are managed already on the C++ side. While testing everything out, any attempt to do the following:

ant = GetAntByID(ID)

in Lua resulted in abort() being called and the program crashing and burning.

R6010
-abort() has been called

I just seem to be missing something with how everything gets shuttled back and forth (this is my first foray into gluing Lua and C++ together beyond toy programs). I'm pretty sure passing a plain pointer isn't the way to do it; lightuserdata seems to be what I'm looking for, but it also has a bunch of restrictions.

So to sum up: What is going on here that causes abort to be called and how can I use Luabind/the Lua C API to get a pointer to a C++ object passed to Lua and call member functions on that pointer as if it were an object (without letting Lua garbage collect it)?

The solution to this problem seemed to be tied to the AntFactory class/member functions being static. As soon as I switched from registering and using this:

//C++

static int AntFactory::CreateAnt(foo, bar)
{}

//Lua

factory:CreateAnt(foo, bar)

to an instantiated object and regular member functions like this:

//C++

int AntFactory::CreateAnt(foo, bar)
{}

//Lua

factory:CreateAnt(foo, bar)

everything worked with no problems at all (after also pushing the factory to the global table). I think the reason for this is that trying to call static member functions on a non-instantiated C++ object fails due to Lua (or Luabind?) not being able to have an object to query for calls.