ActionScript 3.0 :: Text Disappearing From Textfields?

I'm working on an interactive poetry project. I have 49 textfields displayed in a 7x7 grid. The properties are stored in an array. Here is the code for that. For the purposes of demonstration I place the character "S" as text in each field. This code works as intended.

var instances:Array = [];
for (var i:int = 0; i < 49; i++) {
var j_inst:TextField = new TextField();
j_inst.text = "S";

[code]....

The problem occurs when I want to change the text. When it's triggered the text simply disappears. I have no idea why and I'm running out of ideas. I've tried without the embedded font but to no avail. Changing other text properties like instances[j].x works but whenever I change the text I lose it.

function ChangeText(e:TimerEvent):void {
for (var j:int = 0; j < 49; j++) {
instances[j].text = "X";
}
}