Changing text in a textfield

1

My problem: I cannot get the text to change in a

txtField = passedObj.createTextField( "txt_Content", passedObj.getNextHighestDepth(), 40, 40, 200, 1000 );

txtField.text = "wheioaheiowa4";
txtField.embedFonts = true;
txtField.antiAliasType = "advanced";
txtField.sharpness = 300;
txtField._quality = "BEST";
txtField.selectable = false;
txtField.multiline = true;
txtField.autoSize = true;
txtField.wordWrap = true;
txtField.type = "dynamic";

var txt_Fmt:TextFormat = new TextFormat();
txt_Fmt.size = 16;
txt_Fmt.color = 0xFFFFFF; 
txt_Fmt.font = "Arial";
txtField.setTextFormat(txt_Fmt);

The following code works, but ONLY if it’s in the same class. If I call it on the textField from another class, it does not replace the text. Instead it displays “BLAH” above the old textField, but in the debugger does NOT create a new textField. (So you see “BLAH” and “wheioaheiowa4” overlapped).

txtField.replaceText( 0, txtField.text.length - 1, "BLAH");
txtField.replaceText( txtField.text.length-1, txtField.text.length, "");

ANY suggestions would be appreciated, or some good links to solid ways of manipulating dynamically created text.