>An important section of the HTTP header required by our server to access this option has been hidden by your browser. This is usually related to users behind proxies where the proxy is hidding this information. In order to use this option, you need to make sure your proxy does not block this standard information. You may adjust or contact your network administrators

You will find related information in the technical guideline document at http://www.levelextreme.com/technicalguideline.asp.