OLK 2003 Calendar permissions cannot be saved

[Barkley Bees]

I have one user (XP + OLK2003) who, for some reason, cannot save any
permission changes to his calendar (ie: adding a reviewer to the calendar).
I checked his mailbox that his permissions were ok on Exchange (2003) and
created a new Outlook profile on his client. Both to no avail. Has anyone
seen a similar situation and found a solution?

 

[Roady [MVP]]

What happens when he tries? "Cannot" is a much too vague term to work with
to offer any meaningful responses.

 

[Barkley Bees]

Oh! I should have been more specific. When attempting to save a permission
change to the calendar, it says (apologies, the client is not an English
version OS) the equivalent of "could not save the changed access
permission".

 

[Roady [MVP]]

Some follow up questions;
Is this only for the Calendar?
Does setting permissions on other folders work as expected?
Is the client directly connected to Exchange on the local network or is the
connection being made via a VPN or RPC over HTTP?
Is Cached Exchange Mode enabled? Does turning it on/off make a difference?