exchange server 2003/ outlook 2002 and 2003 and public folders

I an trying to set up a master contacts list in public folders.
I am able to creat a folder bur when I try to save to this folder i get:-
the item could not be saved to this folder. the folder has been deleted or
moved, or you do not have permission.
I have checked permissions and they seem correct.
I then tried to to set up a mail content folder and this worked like a dream
I can read/write adjust user access no problem.

Please if you could through some lite on this matter I would be gretfull

Tom