Problems with subsequent instances of a JS object in IE6

I got a little problem with IE6 which doesn't appear on Chrome or Safari or Firefox. All is working fine except one thing: my web app defines a constructor/prototype from which I create multiple instances like this:

var app = {};

app.mapConceptFirst = new MapConcept("#first");

app.mapConceptSecond = new MapConcept("#second");

app.mapConceptThird = new MapConcept("#third");

Here's the constructor:

function MapConcept(id) {

    this.currentNavigator = "";

    this.start = 0;

    this.angle = 0;

    this.clientX = 0;

    this.clientY = 0;

    this.currentMenu = 2;

    this.h = 0;

    this.w = 0;

    this.itemList;

    this.firstRotation = 0;

    this.section = id;

    $(window).resize(function () {

        this.h = $(window).height();

        this.w = $(window).width();

    });

    jQuery.preLoadImages("images/anneau.png", "images/anneau1.png", "images/anneau2.png", "images/anneau3.png", "images/anneau4.png");

    this.currentNavigator = BrowserDetect.init();

    this.init();

    this.getItems();

}

Unfortunately, on IE6 the first instance works fine, all my stuff is running, but the second and third ones don't work. How can I solve my problem ?