ActionScript 3.0 :: Starting Animations For All Objects In Array

I've defined an array and want all the objects to start playing their animations when the project opens. Here's the relevant code (with only the first object playing the animation so far):

ActionScript Code:
var coinArray:Array = [coin1, coin2]; //an array which contains all of the coins
var numCoinArray:int = coinArray.length; //how many objects are in the coinArray
function init() //Loads assets to the stage and starts animations
{for(var i:int = 0; i< numCoinArray; i++)//set i to 0; if i is < numLevelArray perform code below; +1 to i {
var o:DisplayObject = coinArray[i]; //gets the object at index i,
o.gotoAndPlay(1); //perform operation on that object
}}

The error I'm getting at the moment is the line "o.gotoAndPlay(1)" where I get this error in the output section:
"Call to a possibly undefined method gotoAndPlay through a reference with static type flash.display: DisplayObject."
I'm presuming that the code line above "var o: DisplayObject = coinArray[i];" is the problem and should be changing DisplayObject to something else, I'm just not sure what?