ActionScript 3.0 :: Grid - Making Each Object Wait Before Clicking

I've been working a game where you drag an object onto a grid. This then 'grows' over time. Once it has taken about 5 seconds to grow, the player can click on it (only 5 seconds for debugging reasons) and 'collect' money as a result. The problem I'm having however. Is that I cannot remove it once the timer even has occurred. I get the 2007 parameter error, child must be non null. Problem is, I don't see how it is null as I've already defined it? I'm rather lost - and somewhat new to AS3.

Code:
private function placeSeeds(e:MouseEvent):void {
var seedsRow:int=Math.floor((mouseY-300)/75);
var seedsCol:int=Math.floor((mouseX-150)/65);
// check tiles
if (seedsRow>=0&&seedsCol>=0&&seedsRow<3&&seedsCol<3&&itemsArray[seedsRow][seedsCol]==0) {
var placedSeeds:lolMC=new lolMC();// constructs the object
[Code] .....