Calendar view (custom) can’t read or open view (Exchange 2003/outlook2007)

Hello,
This is my second post. Domain users with Vista + Outlook 2007 have an error message on custom views in a shared calendar. The shared calender and views are created from a PC with WinXP+Outlook 2003 and stored on Exchange 2003. The views work OK for one day. Next day, usually early in AM, about 1-2 hours after everyone is logged in, some (not all) views get this message. Other users win WInXP+Outlook2003 don’t have message and still can see the views.

Also, if I edit and save an OK view, from PC with WinXP+Outlook2003, the Vista users get message.

Only solution to date, is create a new view with new name.

All PC and servers are up to date with most recent SPs (as of jan 2009).

Any ideas?
thx