Movieclip associated with array index

1

Alrighty here is my code:

function setButtons() {
	trace (_root["questionArray"+questionNum][0]);
	for (i=0; i<=_root["questionArray"+questionNum].length; i++) {
		trace (_root["questionArray"+questionNum]*);
		_root["questionArray"+questionNum]*.gotoAndStop(2);
	}
}
setButtons();

so when I trace (_root[“questionArray”+questionNum][0]); it comes out as radio1 however the second trace (_root[“questionArray”+questionNum]*); is undefined. Why?