IE's process doesn't have the URL property (like any other process). You need to use the Page object:
<font class="small">Code:</font><hr /><pre>...
var ie = Sys.Process("iexplore");
var page = ie.Page("*");
if(page.URL == "http://qa2-d") // do something
As for the "Window.URL" help topic, it means that Firefox and applications that use WebBrowser controls have the URL property assigned to windows that host the page. Again, this property is assigned to one of their windows, not to the process itself.