Loading Random Movie Clips From The Library

(****another title for this could be “how to create a MovieClip variable”)
basically, im trying to load random movie clips from the library when i run the function “TRO1”…
the logic behind what im trying to do is to to first create an array containing the class names (name given in the “linkage” option) of the movie clips in the library… then randomly select an item from that array… then bring it to the stage…
Here is the code I typed:

var characterArray:Array = [“truck”, “car”, “boat”, “train”, “helicopter”]

function TRO1(event:Event):void
{
var randomCharacter = characterArray[Math.floor(Math.random() * characterArray.length)];
var character:MovieClip = new randomCharacter();
addChild(character);
trace(“character is on stage”);
}

stage.addEventListener(MouseEvent.CLICK, TRO1);

When i try to run the function, i get the error message “Instantiation attempted on a non-constructor…”

I think the problem is that flash doesn’t understand what “randomCharacter” is in the line “var character:MovieClip = new randomCharacter();”… I assume there is a proper way of writing the “randomCharacter” variable so that i can use it in the succeeding line…

Any ideas on how to re-write this code?