Unable to edit contact in Public folder

Two years ago, I installed E2K at a customer place. They created many subfolders containing many contact. 18 months later, their server crashed. I Setup a new server and have been able to restore their mailboxes and public folders.
The problem is that after one week, they can read anything in old created contact in public folders but they cannot modify or delete any.
They are able to create new one in those contact subfolder.
How may I resolve this issue to allow users to modify old contactsand allow administrators to give permissions on different old subfolders to others?
I think that it could be an old SID from the first installation still registered in the subfolders. I don’t know.
Any help will be appreciate.
Christian