[solved] C2440 error.... wtf.

#ifndef VE_MATERIAL_HPP
#define VE_MATERIAL_HPP

namespace render
{
	class ShaderGpu;
	class ShaderCpu;

	// basic material interface class
	class IMaterial : public core::IUnknown
	{
               // code removed
	};


	//--------------------------------------------------------------
	// material manager class, not singleton

	class MaterialManger : public core::IUnknown 
	{
	public:
		virtual int createMaterial( std::string materialFile );
		virtual int rebuildMaterial( std::string materialFile, int replaceID );

		virtual void loadDirectory( std::string dir );	

		virtual IMaterial* getMaterial( int id );

		virtual ~MaterialManger();
		MaterialManger();

	protected:
		std::vector< IMaterial* > materials;
	};

};

#include "engine.hpp"
#include "material.hpp"

namespace render
{

//---------------------------------------------------------------
MaterialManger::MaterialManger() 
	: IUnknown( "MaterialManager" )
{
}

//---------------------------------------------------------------
MaterialManger::~MaterialManger()
{
}

//// SOURCE REMOVED FROM HERE

}; //namespace