Trouble with loadVars Variable

I am modifying a quiz that imports a number from an external text file in order to tell flash which xml file to load (the file that has the quiz questions). The variables seem to load (I’ve checked list variables), but when I try to concatenate the variable I get an ‘undefined’. How to I call this variable?

[FONT=Courier New]//loadVars from Data Source
myVariables = new LoadVars();
myVariables.load(“data.txt[/FONT][FONT=Courier New]”);
myVariables.onLoad = function(success){
if(success){
trace(this.[COLOR=red]quiznumber[/COLOR]);
} }[/FONT]
[FONT=Courier New][/FONT]
[FONT=Courier New]//Generate Question Array
var quizItems=new Array();
var myData=new XML();
myData.ignoreWhite=true;
myData.onLoad=onQuizData;
myData.load(“quiz[/FONT][FONT=Courier New]”+[COLOR=red]quiznumber[/COLOR]+".xml");
stop();[/FONT]