prova così

myData = new LoadVars()
myData.load("countdown.asp")
myData.ref = this
myData.onLoad = function(success){
if(success){
for(var i=0; i<this.cant; i++){
this.ref["Title_txt"+i].text = this["Title"+i]
this.ref["Comments_txt"+i].text = this["Comments"+i]
onload_data();
}
} else trace("Error loading data")
}
function onload_data(){
Title0 = Number(Title_txt0);
Title1 = Number(Title_txt1);
Title2 = Number(Title_txt2);
Title3 = Number(Title_txt3);
Title4 = Number(Title_txt4);

function countdown(){
dat = new Date();
dat2 = new Date(Title0, Title1, Title2, Title3, Title4, 0, 0);
dif = (dat2-dat);
g_rim = int(dif/((60000*60)*24));
o_rim = int((dif/(60000*60))-(g_rim*24));
m_rim = int((dif/(60000))-(((g_rim*24)*60)+(o_rim*60)));
s_rim = int((dif/1000)-((((g_rim*24)*60)*60)+((o_rim*60)*60)+(m_rim*60))) ;
giorno = g_rim;
ora = o_rim;
minuti = m_rim;
secondi = s_rim;
if (giorno < 10) {
giorno = "0" + g_rim;
}
if (minuti < 10) {
minuti = "0" + m_rim;
}
if (ora < 10) {
ora = "0" + o_rim;
}
if (secondi < 10) {
secondi = "0" + s_rim;
}
}
tempo = setInterval(countdown, 1000, Title0, Title1, Title2, Title3, Title4);
}