Problem with CCLayer::setIsTouchEnabled(true)

cocos2d-x C++
#1 
class SelectScene : cocos2d::CCLayer
{
public:
    float g_width,g_height;

    virtual bool init();  
    static cocos2d::CCScene* scene();
    LAYER_NODE_FUNC(SelectScene);
    void ccTouchesBegan(cocos2d::CCSet* pTouches, cocos2d::CCEvent* pEvent);
    void onExit();
    int counter;
};

then call setIsTouchEnabled in init()
bool SelectScene::init()
{
    do 
    {
    CCLayer::init();

        ......

        this->setIsTouchEnabled(true);


        CCLog("SelectScene completed");
        return true;
    } while (0);

    return false;
}

Then it cause an error in CCTouchHandler.cpp at dynamic_cast(pDelegate)->retain(),before I actually see the SelectScene(a layer).

bool CCTouchHandler::initWithDelegate(CCTouchDelegate *pDelegate, int nPriority)
{
    CCAssert(pDelegate != NULL, "touch delegate should not be null");

    m_pDelegate = pDelegate; 

    dynamic_cast(pDelegate)->retain();

    m_nPriority = nPriority;
    m_nEnabledSelectors = 0;

    return true;
}

dynamic_cast(pDelegate) returns NULL,leading to crash down.

Please help me with this problem.It really make us crazy.