Each year we create a PST that contains all the company holidays for that
year. Whenever we create a new user account/mailbox, the Exchange admins will
open up the new user's calendar and import the new holidays into the calendar.

What is happening now is that some admins are now able to import and others
are NOT able to import the holidays from the same PST. The ones who can
import are using Office 2007 (the beta) and the ones who cannot import are
using Office 2003.
The only error they get when they attempt to import the PST is "The Item
could not be found".
Once they log in to the workstation using Office 2007 beta, they can import
without any problems using the same PST that didn't work before.
To make things even more mysterious, if you log on AS the new user account,
you can import the PST using Office 2003 just fine. This ONLY seems to be
happening when you try to import into a calendar you have opened from within
your own Outlook profile.

Any ideas why this might be happening and how to fix it (short of installing
Office 2007 beta on the admin's machines)? I know we can import the PST using
exmerge, but that seems like overkill for such a simple task.

Dave