http://jetlounge.net/blogs/teched/archive/2009/06/30/how-to-enable-report-builder-to-launch-from-a-sharepoint-site-when-using-forms-authentication.aspxWhen your Reporting Services instance is integrated with a SharePoint product or technology and you use Forms authentication, you might encounter the following error when you launch Report Builder: "Cannot Start Application. Cannot continue. TheenCommunityServer 2007.1 (Build: 20917.1142)