Before you start profiling a Silverlight application, make sure that:
Silverlight 4 Developer Runtime or higher is installed. You can get the runtime at the official Microsoft Silverlight website.
A website with your Silverlight application has started using the Visual Studio Development Server or any other web server.
To profile a Silverlight Application, you should specify the following parameters:
URL to invoke the Silverlight application. If no URL is provided, dotTrace will launch a blank page in the specified browser.
A browser that should run the application you profile. The default system browser is pre-selected.