Single User Unable to use Mail

Question

Running Snow Leopard Server on a Mac Mini, hosting our own email. I've got about 25 email accounts setup, and all have been functioning swimmingly for months. Earlier this week, for no reason that I can think of, one account started malfunctioning. That's right, just one of 'em.
The user opens Apple Mail, and we get the spinning wheel indicator next to this particular inbox, and it literally takes 5-10 minutes for new messages to populate. Then when we click on one of the messages, the message body frame displays a "loading" message that remains there indefinitely.
This first happened over the holiday weekend, and on Tuesday I repaired permissions on the server, and this seemed to solve the problem, but only for about 12 hours. Now repairing permissions has no effect.
In server admin, I had a look at the mail service logs, and there is a constant stream of errors referring to this particular inbox that look something like this:
Sep 8 17:24:35 elvis dovecot[68]: IMAP(*): filedotlockopen() failed with file /var/spool/imap/dovecot/mail/1DCE9535-FF8E-4F0E-9921-1FE89108A583/dovecot.index .log: Permission denied
Sep 8 17:31:30 elvis dovecot[68]: IMAP(*): filedotlockopen() failed with file /var/spool/imap/dovecot/mail/1DCE9535-FF8E-4F0E-9921-1FE89108A583/dovecot.index .log: Resource temporarily unavailable
I'm a total server novice, so let me know if there is any other information that would be helpful in diagnosing this problem. Thank you very much for reading this!

Answer 1

the user directory (the mumble jumble such as :
3F6BEDAF-CEBC-4DE6-9665-15F71DD53045
should be set to:
drwx------ 21 jfmezei mail ( jfmezei being the username of the user)
the d means "directory".
rw = read write
x= execute (aka: you can list contents of directory).
All the files inside that directory will have the same owner/group.
Directories will havce drwx and other files will have rw only.
Once into that user's directory with the cryptic name, you can:
stat * will give you a list of files, their file security, onwer and group (along with a whole bunch of other stuff). You can verify that the files are owned by the correct user and the group is set to "mail".
More info on the unix security of files:
http://developer.apple.com/library/mac/#documentation/OpenSource/Conceptual/Shel lScripting/ShellScriptSecurity/ShellScriptSecurity.html
You can also read up on:
http://developer.apple.com/library/mac/#documentation/Security/Conceptual/Securi tyOverview/Concepts/Concepts.html#//appleref/doc/uid/TP30000976-CH203-CHDJJGBF
Look for: Mac OS X File System Security