The issue with the fonts can be resolved by adding the following stylesheet to your application. <link href="http://serverapi.arcgisonline.com/jsapi/arcgis/2.3/js/dojo/dijit/themes/claro/document.css" rel="stylesheet" type="text/css">
As for why the map isn't loading its hard to diagnose the issue without seeing your application or the code. Is the broken site publicly available? If so can you post a link?