After an event. (timer or setInterval?)

On frame three of a movie I’m working on I have an alpha fade that takes 3 seconds to complete. Once finished (ie - this._alpha = 0) I want the movie head to go to frame 4.

My alpha fade looks like this on a mc instance:
onClipEvent (load) {

this._alpha = 100;
this.alphaTo (0, 10);

}

That works fine but every attempt of either a setInterval or _root.gotoAndStop(4); either gives me an error or simply goes to frame four without doing the fade first.

Seems pretty simple but I’m lost.