“The operation failed. An object could not be found. Unable to..."

[Milton]

Hello to all,

I have a Outlook issue with one specific user (Secretary) & Outlook
calendaring.
Before when any user incl. the (Secretary) wanted to create a “New
Appointment†or “Meeting Request†what they would do is, go to calendar
select the day & hour, “invite attendees†send it & it was done.
From one day to the next we have a problem with the (Secretary) in the
“Invite Attendees†box, if we add the (Secretary) or a group in which she is
in, in the “Required†or “Optional†box there’s no problem but if we add the
(Secretary) or group in which she’s in, to the “Resources†box when we choose
“send†we get a message saying “The operation failed. An object could not be
found. Unable to directly book a resource for this meetingâ€. All the users
have Win XP Pro Eng with updates & SP2, Office 2003 with SP1,2 & updates,
we’ve deleted the user & created a new one with the same name, & nothing.
Please if anyone knows what could be the problem or if anyone has
experienced the same situation and managed to solve it, let me know.

Thanks to all.
Milton