Calendar entries not visible with Cached Exchange Mode enabled

I have one user whose calendar entries are not displayed when Cached Exchange Mode is enabled on my PC.
He has a Mac and is using Entourage 12.2.0. There are other Mac users with the same version of Entourage whose entries are displayed.
If I turn off Cached Exchange Mode, the calendar entries are visible.
We are running Exchange 2007 server with Outlook 2007.
Any help would be appreciated!