Microsoft Exhange Mailboxes. Cannot find certain items.

Basically the problem I am having is when our symantec backup exec completes every night, It finishes with an access denied error.
This error is linked to an item in one persons mailbox.
The error I get from Symantec backup:
Access denied to file USERS NAME [users name]Top of Information StoreDeleted ItemsRe: hello.

When I try to search for this item in the mailbox it is not there.

If anyone can help me find and delete this annoying item then I would be very greatful.

Regards