[Error Code] E:FreeBusy gsync32!FreeBusyServer:: ValidateOutlookFreeBusy Config [Explanation] 
Free busy will not work. Under the registry key HKLM\SOFTWARE\Microsoft\Office\12.0\Outlook\ SchedulingInformation\FreeBusySupport, you need to set the value 'SMTP' to the string '{0006F049-0000-0000-C000-000000000046}'. Currently it is set to '(null)'.