ErMsg[findIndexF(i)]._alpha= 100;

I want to be able to make the relevent ErMsg to alpha 100 if infoDats0 or infoDats1 text length is <=1. Below is my code and can't get it to work?

var chkEk:Array = [chkE0, chkE1]

var theTFa = new Array(infoDats0, infoDats1)

var ErMsg = new Array(Field0, Field1) // alpha is set to 0 at the start

function findIndexF(tf:TextField):Number{

          for(var i:Number=0;i<theTFa.length;i++){

                    if(tf==theTFa){

                              return i;

                    }

          }

};

goUp_btn.onRelease = function() {

var chkE0 = infoDats0.text.split(' ').join('');

var chkE1 = infoDats1.text.split(' ').join('');

          for(i=0; i<theTFa.length; i++){

                    if (chkE0.length>1 && chkE1.length>1){

                              //doSome

                    } else {

                              if (chkEk.length<=1){

                                        ErMsg[findIndexF(i)]._alpha= 100; //not working

                              }

                    }

          }

};