One of our executive assistants is having the following issue:

She is a reviewer for one of the corporate execs. From her account, she
sends out a meeting request to some X number of users, including the two
users for whom she reviews.

She then receives two meeting requests (from her), but for the users that
she is a reviewer for. When she goes in to accept the meeting requests, she
gets the following error when clicking "Accept":
"The function cannot be performed because the object has been deleted"

If Outlook is closed and re-opened, the user is then able to accept the
meeting requests, no problem.... The issue is sporadic, cannot be
consistently reproduced.

User is on Outlook 2003 SP3, connecting to an Exchange 2007 server. User is
on cached mode.