IIS backward compatibility components were not detected
Upgrade Advisor did not detect IIS components and settings that provide information used by Setup to create new Reporting Services URLS.
IIS includes components that provide information about the report server and Report Manager virtual directories, and those components are not installed on the report server computer. Upgrade can continue, but URLs for the report server or Report Manager will not be recreated by upgrade.
After upgrade finishes, use the Reporting Services Configuration tool to set the URLs for report server or Report Manager. Use IIS Manager to remove the virtual directories you no longer need.
For more information, search for "How to: Configure a URL (Reporting Services)" in SQL Server Books Online.