ActionScript 3.0 :: Accessing Methods And Properties Via GetChildByName

I seem to be having a bit of a problem here. I'm generating a load of class instances using the following code:

maxpersons=25;
for (var i:Number=1;i<=maxpersons;i++)
{
var person:Person = new Person;

[Code].....

OK. I then need to run through each of them and check for a collision with an object from the main stage (called redDot), which I pass to a method (called doDamage) within the class. I'm using the following code:

for (i=1;i<=maxpersons;i++)
{
if (game.getChildByName("person"+i).hitTestObject(red Dot))
{
game.getChildByName("person"+i).doDamage(redDot);
}
}

I keep getting an error saying "1061: Call to a possibly undefined method doDamage through a reference with static type flash.displayisplayObject."!

It just won't work. I've tried altering the code to:

game["person"+i].doDamage(redDot);

but I get an unexpected trace output saying "TypeError: Error #1010: A term is undefined and has no properties."