[Dovecot] deliver looking into root directory for sieve configuration ?

[Guillaume Hilt]

    Hi,

I'm using dovecot (+sieve), dspam, clamav and postfix with wirtual users 
and domains.
When the server receive an email, I get this error :
Jan  2 14:48:52 mail postfix/qmgr[13573]: 89DE1276C42B: 
from=<postmaster at shadowprojects.org>, size=926, nrcpt=1 (queue active)
Jan  2 14:48:52 mail deliver(postmaster at adomain.fr): chdir(/root) 
failed: Permission denied
Jan  2 14:48:52 mail deliver(postmaster at adomain.fr): 
stat(/root/.dovecot.sieve) failed: Permission denied
Jan  2 14:48:52 mail deliver(postmaster at adomain.fr): 
msgid=<495E1B33.5020009 at shadowprojects.org>: saved mail to INBOX
Jan  2 14:48:52 mail postfix/lmtp[13584]: 89DE1276C42B: 
to=<postmaster at adomain.fr>, 
relay=mail.mydomain.com[/var/run/dspam/dspam.sock], delay=0.07, 
delays=0.05/0/0/0.01, dsn=2.6.0, status=sent (250 2.6.0 
<postmaster at adomain> Message accepted for delivery)

Why does it look inside the /root folder for sieve configuration ?
All virtual mailboxes are in /home/vmail/DOMAIN/USER/.maildir (owned by 
postfix:postfix; dspam has been put in the postfix group)

I uploaded the following config files in http://hiltg.pastebin.com/ :
- main.cf
- master.cf
- dovecot.conf
- dspam.conf

(mails are supposed to be delivered to the mailbox by dovecot, which is 
called by dspam)

Any idea please ?

Thanks and happy new year to you all,

-- 
  Guillaume Hilt