geoserver - Cannot populate a Ext GridPanel through GeoExt WMSCapabilitiesStore

I've been working through a few tutorial/starter map samples on the OpenGeo and GeoExt websites and have come upon a problem I cannot solve. I'm trying to load a list of layers from my GeoServer into a GridPanel using GeoExt.data.WMSCapabilitiesStore. No matter what I try, I cannot get anything to show in the GridPanel. I thought I had cross domain issues at first, but the problem persists even when the webpage and the GeoServer data are on the same server.

Here's a link to my very barren looking web map: http://24.105.210.45/OpenGeoGeoExtMap1.html.

Here's the JavaScript that's supposed to access the wms and load the layer list:

    Ext.onReady(function() {
var grid = new Ext.grid.GridPanel({
    title: "Available WMS Layers",
    region: "north",
    height: 150,
    viewConfig: {forceFit: true},

    store: new GeoExt.data.WMSCapabilitiesStore({
        url: "http://24.105.210.45:8080/geoserver/wms?service=wms&version=1.1.1&request=GetCapabilities",
        autoLoad: true
        }),
        columns: [
            {header: "Name", dataIndex: "name", sortable: true},
            {header: "Title", dataIndex: "title", sortable: true},
            {header: "Abstract", dataIndex: "abstract"}
            ],

Any help with this, or just ideas of where to look next would be greatly appreciated.

Answer

Different port numbers are considered as different domains - even if the rest of the URL is the same. So if your main site is running on:

http://24.105.210.45:80

You would need a proxy to access:

http://24.105.210.45:8080/geoserver/wms?service=wms&version=1.1.1&request=GetCapabilities

So the proxy FAQ below applies in your case:

http://trac.osgeo.org/openlayers/wiki/FrequentlyAskedQuestions#ProxyHost

Why can't you run both your web application and Geoserver on the same port?

Update:

You can also get around the same domain policy using YQL - http://geographika.co.uk/accessing-cross-domain-data-with-yql