How to make at startup script that fits spread on open

Hi there,

Does anyone know how to make a startup script for InD CS6 that fit spread too screen when document open?

I've tried this and it works but I've get a dialog that says "Object is not valid":

#targetengine "session"

main();

function main(){

var myEventListener = app.eventListeners.add("afterOpen", excuteScript);

}

function excuteScript(){

var myD = app.documents[0];

app.layoutWindows[0].zoom(ZoomOptions.FIT_SPREAD);

}