Imap message - setHeader problem

Question

on gmail server does not work changing on header (since today... yesterday everytging was ok...)
            Message m = f.getmessage(0);
            MimeMessage mime = new MimeMessage((MimeMessage)m);
            mime.setHeader(
                    "ABC",
                    new Date()
            mime.setFlags(new Flags(Flag.DELETED), false);
            try {
                f.appendMessages(new MimeMessage[] {mime});
                m.setFlag(Flag.DELETED, true);
            catch(Exception ex) {
                log.debug(ex.getMessage());
            f.expunge();
            f.close(false);I avoided connecting to store, getting session.
Problem is how to change header in ImapMessage - on other servers (aol, vfemail) everything works fine, on gmail everything was ok until yesterday... I don't know whats going on? Does gmail blocks setting headers? Is it possible to block something like this?
And second question - is it possible to change (or set) header to message without downloading, deleting and sending other instance of the same message on server? what in case when message contains attachments? this operation won't be efficient... this does not have any sense, imap should be fast so he should download only headers (subject, from) and the rest when message should be downloaded.
I have problem with synchronizing messages which are on server with messages in database. Does exist way to identify message 1 to 1? When I will get data from DB can I tell that on server exists EXACTLY one message which I want to download?

Answer 1

Thanks for the responses ..
yes, actually, I have tried reconstruct from mailbfr (options -o and -m) as well as via cyradm.. and SA
either option succeeds at reconstructing all the boxes fine, and permissions appear to be fine as well..
drwxr-xr-x 4 cyrusima mail - 136B Jun 3 2006 mailstore
mailbfr reports both partitions being operated on ..
my config also appears OK, its the same as has been working flawlessly for over a year :
admins: cyrusimap localadmin
configdirectory: /var/imap
partition-default: /var/spool/imap
unixhierarchysep: yes
altnamespace: yes
servername: mail.mydomain.com
sievedir: /usr/sieve
sendmail: /usr/sbin/sendmail
lmtpdowncasercpt: 1
tlscertfile: /etc/certificates/mail.mydomain.com.crt
logrollingdays: 0
logrolling_daysenabled: false
tlskeyfile: /etc/certificates/mail.mydomain.com.key
imapauth_crammd5: yes
imapauthgssapi: yes
popauthclear: no
enable_pop: no
tlscommonname: mail.mydomain.com
tlsserveroptions: use
imapauthlogin: yes
partition-mailstore: /Volumes/path/to/alt-partition
I did notice an odd thing though..
although the boxes are being read from /var/spool/imap
and accounts show "default" partition (in SA)
when I try to create a box (via Mail.app) in IMAP acct..
it fails .. can't so it ..
and the IMAP log shows
imaps[22176]: IOERROR: creating directory /Volumes/path/to/alt-partition: Permission denied
so it appears to want to write to the right place and can't ..
but still reads from the wrong place.
something is amiss !!
where to look next ?