How can i remove when i use CCSpriteBatchNode

I practice in this example
http://www.cocos2d-x.org/projects/cocos2d-x/wiki/Step_by_Step_Cocos2dxSimpleGame_Series
Finally, can be successfully run
Now I want to make program efficiency.

So i use CCSpriteBatchNode and CCSpriteFrameCache
But projectile hitting the enemy will not disappear

this is my project
http://www.funp.net/482727
can someone help my to fix it
thx you