Ithe item could not be deleted

“It was either moved or already deleted, or access denied.”
I’ve already read Q195863. This has happened to an email that was sent from a mac with a mac file on it. The client opening the mail can read it, but cannot delete or move the email at all.
He’s on a Win2k pro box with Outlook 2k.
He’s asked me for help. So, I have had her send to me, and now I have an email that’s stuck to my box! I can find nothing in the Exchange 2k that could help us with this aggrivating email.