{DCEDFCBF-C7D1-4B81-A20F-7524D306135E} is your value for SMTP for the registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\12.0\ Outlook\SchedulingInformation\FreeBusySupport ??
Did you have the "Microsoft Outlook Connector" installed at one point, or do you have it installed now? Then it's using that freebusy provider, and that's why you can't see your info.
Try replacing that SMTP value with
{0006F049-0000-0000-C000-000000000046} |