If you have already begun installing the SharePoint Server 2010 Beta on Microsoft Windows Server 2008 R2 or Microsoft Windows 7 you may have already encountered the following error when provisioning Service Applications or when accessing pages that make service calls:
“System.Configuration.ConfigurationErrorsException: Unrecognized attribute ‘allowInsecureTransport’. Note that attribute names are case-sensitive. (C:Program FilesCommon FilesMicrosoft SharedWeb Server Extensions14WebClients<Service Area>client.config line <Line Number>)”
To resolve this issue you will need to download the KB976462 hotfix which can be found at http://connect.microsoft.com/VisualStudio/Downloads/DownloadDetails.aspx?DownloadID=23806.