MS CRM 2013 - Reporting Extensions Setup (Blank/Empty SSRS Instance)

When installing CRM 2013 Reporting Extensions, you may experience the "Empty SSRS Instance" dropdown on the second install wizard screen as displayed below:

This can be caused by any of the following reasons:

• You are trying to install "Reporting Extensions" on the incorrect server, you should be running the installer on the SQL Server not the CRM Server.
• SSRS is incorrectly configured, it is not configured or pointing to a Report Server database, a permisions or virtual directory issue. Try loading the Reports web page using IE to check that the Reporting URL can be reached.
• You have installed an unsupported version of SQL Server

In my experience, the 3rd is the most likely cause where by an x86 version of SQL has been installed. Once you have resolved the cause, you should now see the SSRS instance within the dropdown: