Pb Postfix -> Help!

Salut à tous,
j'ai visiblement un petit problème de config sous Postfix (qui tourne avec
Mailscanner). Il semble que certains répertoires (Bouce, defer entre
autre) n'aient pas les droits corrects.
J'obtiens dans les logs des messages du style:
Jun 4 08:52:06 liam postfix/bounce[28958]: warning: refusing to mkdir
bounce/2/7: parent directory is writable by everyone
Jun 4 08:52:06 liam postfix/bounce[28958]: fatal: open file bounce
272BD13C04E: Operation not permitted
Jun 4 08:52:06 liam postfix/bounce[28960]: warning: refusing to mkdir
bounce/A/9: parent directory is writable by everyone
Jun 4 08:52:06 liam postfix/bounce[28960]: fatal: open file bounce
A952513C056: Operation not permitted
Jun 4 08:52:07 liam postfix/bounce[28964]: warning: refusing to mkdir
defer/2/7: parent directory is writable by everyone
Jun 4 08:52:07 liam postfix/bounce[28964]: fatal: open file defer
272BD13C04E: Operation not permitted
Jun 4 08:52:07 liam postfix/local[28956]: warning: premature end-of-input
from private/bounce socket while reading input attribute name
Jun 4 08:52:07 liam postfix/master[28705]: warning: process
/usr/libexec/postfix/bounce pid 28960 exit status 1
Jun 4 08:52:07 liam postfix/bounce[28965]: warning: refusing to mkdir
defer/A/9: parent directory is writable by everyone
Jun 4 08:52:07 liam postfix/bounce[28965]: fatal: open file defer
A952513C056: Operation not permitted
Jun 4 08:52:07 liam postfix/smtp[28959]: warning: premature end-of-input
from private/bounce socket while reading input attribute name
Jun 4 08:52:07 liam postfix/master[28705]: warning: process
/usr/libexec/postfix/bounce pid 28961 exit status 1

De quel dossier parent s'agit-il? Mes répertoires bounce et defer
appartiennent à postfix:postfix avec des droits 0700
Quelqu'un a une idée?
Est-il possible de rétablir les droits sur les répertoires à partir du
fichier /etc/postfix/postfix.files?
DG