As-tu déclaré EKA_ACCROUPIR dans l'enum EKEY_ACTION?

Dans include/SKeyMap.h, tu dois avoir :

// Copyright (C) 2002-2011 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#ifndef __S_KEY_MAP_H_INCLUDED__
#define __S_KEY_MAP_H_INCLUDED__

#include "Keycodes.h"

namespace irr
{

	//! enumeration for key actions. Used for example in the FPS Camera.
	enum EKEY_ACTION
	{
		EKA_MOVE_FORWARD = 0,
		EKA_MOVE_BACKWARD,
		EKA_STRAFE_LEFT,
		EKA_STRAFE_RIGHT,
		EKA_JUMP_UP,
		EKA_CROUCH,
		EKA_ACCROUPIR,  /////////////////////////////////////////////////    LIGNE A AJOUTER ABSOLUMENT AVANT EKA_COUNT
		EKA_COUNT,

		//! This value is not used. It only forces this enumeration to compile in 32 bit.
		EKA_FORCE_32BIT = 0x7fffffff
	};

	//! Struct storing which key belongs to which action.
	struct SKeyMap
	{
		SKeyMap() {}
		SKeyMap(EKEY_ACTION action, EKEY_CODE keyCode) : Action(action), KeyCode(keyCode) {}

		EKEY_ACTION Action;
		EKEY_CODE KeyCode;
	};

} // end namespace irr

#endif

J'ai marqué la ligne que tu es censé avoir ajoutée avec "///////////////////////////////////////////////// LIGNE A AJOUTER ABSOLUMENT AVANT EKA_COUNT".