Installing Microsoft dynamics reporting extensions

I am installing Microsoft dynamics reporting extensions and getting the following error

Could not find a part of the path 'E:\Program Files\Microsoft SQL Server\MSRS13.MSSQLSERVER\Reporting Services\ReportManager\web.config'.   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)

The issue appears to be that the  ReportManager is missing!

SQL reporting services is installed and all checks are passed when the installation in performed but it unfortunately fails with the above error. Any ideas why this is missing ?

Thanks Gman