Parallax Tutorial

I found a similar topic on this forum but the answer wasn’t there anyways, I’m getting into the Cocos2d-x and this tutorial: http://www.raywenderlich.com/11338/cocos2d-x-for-ios-and-android-space-game
At the second step, this parte of the code:
@
void HelloWorld::update(ccTime dt) {
CCPoint backgroundScrollVert = ccp(1000,0) ;
_backgroundNode
>setPosition(ccpAdd(_backgroundNode->getPosition(),ccpMult(backgroundScrollVert,dt))) ;
}
@

Don’t work, my Xcode shows this message : “not match function for call to ccpMult”, I looked for that but I couldn’t find an answer, someone know why that’s happened and can explain to me?
Thank you for the help.

just replace “ccTime dt” on “float dt”