[RESOLVED] Using boost's singleton class

[Mybowlcut]

I'm trying to save myself some time and use boost's singleton class instead of writing my own... but it's giving me some weird error that I can't resolve:

#include <iostream>
#include <string>
#include <map>
#include <exception>

#include "boost/shared_ptr.hpp"
#include "boost/pool/detail/singleton.hpp"

class Surface
{
public:
  Surface()
  {
    std::cout << "Loaded a surface." << std::endl;
  }
};

class Surface_Cache : public boost::details::pool::singleton_default<Surface_Cache>
{
public:
  typedef boost::shared_ptr<Surface> Surface_Ptr;
  typedef std::map<const std::string, Surface_Ptr> surface_cache;
  typedef surface_cache::iterator cache_it;

  Surface_Ptr Load_Surface(const std::string& file_name)
  {
    cache_it it = cache.find(file_name);

    if(it == cache.end())
    { // Add surface.
      Surface_Ptr s(new Surface());
      cache.insert(std::make_pair(file_name, s));
      return s;
    }
    return it->second;
  }
private:
  surface_cache cache;
};

int main()
{
  Surface_Cache::instance().Load_Surface("example.png");

  return 0;
}

1>c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp(39) : error C2248: 'boost::details::pool::singleton_default<T>::singleton_default' : cannot access private member declared in class 'boost::details::pool::singleton_default<T>'
1>        with
1>        [
1>            T=Surface_Cache
1>        ]
1>        e:\everything\programs\boost\boost\pool\detail\singleton.hpp(71) : see declaration of 'boost::details::pool::singleton_default<T>::singleton_default'
1>        with
1>        [
1>            T=Surface_Cache
1>        ]
1>        This diagnostic occurred in the compiler generated function 'Surface_Cache::Surface_Cache(void)'

Why is it complaining?

Cheers.