Problems setting access permissions with sam

[Joshua Baer]

I'm running Cyrus on Redhat Linux with Sendmail.

I've been using it for a few years now and feel fairly familiar with it. We 
have about 50 users and use some shared mailboxes.

A few months ago, we stopped being able to make changes to the ACL. The 
"sam" command appears to work without error and "lam" shows the correct 
info, but then when we test it out using an email client we don't see any 
changes. This applies to both granting and removing access.

In the past, if I wanted to see another user's mailbox in mine, I would 
simply grant myself permissions on that box with a command like:
sam user.john josh all

and then the next time I refreshed my mailbox list it would show up. For 
some reason it doen't work anymore.

My instinct (probably wrong) tells me that somehow the access control 
list  got corrupted or something.

Any ideas? Has anyone experienced this before? Any idea where I should 
start looking?

~Josh