not excluding socket dir?

Hi,

I am trying to backup a mail server but it's complaining about a socket
error..  BUT I thought I was excluding that directory.  The command I'm
using:

/usr/bin/rdiff-backup --exclude /mnt/snap/dev --exclude
/mnt/snap/lost+found --exclude /mnt/snap/media --exclude /mnt/snap/mnt
--exclude /mnt/snap/proc --exclude /mnt/snap/run --exclude /mnt/snap/sys
--include /mnt/snap/var/www --include /mnt/snap/var/spool/imap --include
/mnt/snap/var/spool/mail --include /mnt/snap/var/spool/postfix --include
/mnt/snap/var/spool/rsvp --include /mnt/snap/var/lib/postfix --exclude
/mnt/snap/var/lib/imap/socket --include /mnt/snap/var/lib/imap --include
/mnt/snap/var/lib/squirrelmail --include /mnt/snap/var/spool/cron
--include /mnt/snap/usr/local --exclude /mnt/snap/bin --exclude
/mnt/snap/lib --exclude /mnt/snap/lib64 --exclude /mnt/snap/sbin --exclude
/mnt/snap/tmp --exclude /mnt/snap/usr --exclude /mnt/snap/var
mail_backup::/mnt/snap/ /mnt/backup/backups/mail

And I get this output:

SpecialFileError var/lib/imap/socket/idle.10314 Socket error: AF_UNIX path
too long
SpecialFileError var/lib/imap/socket/idle.10325 Socket error: AF_UNIX path
too long
[snip]

Aren't I excluding the directory properly?

-derek

-- 
       Derek Atkins                 617-623-3745
       [email protected]             www.ihtfp.com
       Computer and Internet Security Consultant