If SharePoint 2007 is configured to use Web SSO authentication by using ADFS v1, when trying to render a RS 2008 Report in SharePoint integrated mode, the following error occurs when clicking on the report:
An unexpected error occured while connecting to the report server. Verify that the report server is available and configured for SharePoint integrated mode. --> The request failed with the error message:
<h2>Object moved to <a href="http://<_ADFS_signin_link_>">here</a>.</h2>
Cause: Please note that this behavior is by design. The reporting Service webpart calls the “SharePoint Proxy Endpoints" (see http://msdn.microsoft.com/en-us/library/bb326209(SQL.90).aspx).
Requests from viewer and management pages are sent through these Proxy Endpoints. Neither code path forwards cookies. As a consequence, ADFS considers the call unauthenticated and redirects to the ADFS login page.
Resolution: To solve this issue, use SharePoint 2010 instead of SharePoint 2007. In SharePoint 2010, the RS webpart viewer and management pages send requests directly to the report server.
As Claims Based Authentication is not supported for SharePoint integration between SharePoint 2010 and Reporting Services 2008, you will also need to use Reporting Services 2008 R2.
SQL Server Support.