Mootools doesn't fire the "onChange" event for Selects in IE7

I'm working with MooTools 1.2.4 and I have a select with an event "change" that works fine in Firefox but when I try to test it in Internet Explorer 7 it gives me an error saying that the select doesn't ha开发者_开发问答ve that property or method: my code is as simple as:

$('zone').addEvent("change",function(E) {
    alert("change");
});

I've tested this code in https://www.jsfiddle.net and it does work in IE7!!! So what am I missing here? do you think that has something to do with my version of MooTools? on the MooTools more?

Seems like you've created a custom version of mootools-core and forgot to include Element.Event in the build - http://mootools.net/core