We recently moved one mailbox from an exchange 2003 server to an exchange 2007 server, and the moved was fine, however, the user and his delegated are unable to open re-occuring meetings for his calendar.
Basically, the executive assistant of the user got this error:
Cannot read one instance of this recurring appointment. Close any open appointments and try again, or recreate the appointment. Outlook freezes, and she have to shut it down.