Comment 2 for bug 242846

Here is what causes the error, I reassign:

Setting up slapd (2.4.9-0ubuntu0.8.04) ...
Installing new version of config file /etc/ldap/schema/README ...
Installing new version of config file /etc/ldap/schema/openldap.ldif ...
Installing new version of config file /etc/ldap/schema/dyngroup.schema ...
Installing new version of config file /etc/ldap/schema/inetorgperson.schema ...
Installing new version of config file /etc/ldap/schema/misc.schema ...
Installing new version of config file /etc/ldap/schema/nis.schema ...
Installing new version of config file /etc/ldap/schema/openldap.schema ...
Configuration file `/etc/default/slapd'
 ==> Modified (by you or by a script) since installation.
 ==> Package distributor has shipped an updated version.
   What would you like to do about it ? Your options are:
    Y or I : install the package maintainer's version
    N or O : keep your currently-installed version
      D : show the differences between the versions
      Z : background this process to examine the situation
 The default action is to keep your current version.
*** slapd (Y/I/N/O/D/Z) [default=N] ?
*** slapd (Y/I/N/O/D/Z) [default=N] ? n
Installing new version of config file /etc/init.d/slapd ...
  Backing up /etc/ldap/slapd.conf in /var/backups/slapd-2.3.35-1ubuntu0.2...
  Backing up /etc/ldap/slapd.conf in /var/backups/slapd-2.3.35-1ubuntu0.2... done.
  Upgrading BDB 'checkpoint' options...
  Upgrading BDB 'checkpoint' options... .
  Moving old database directories to /var/backups:
  - directory dc=blaireau...
  - directory dc=blaireau... done.
  Loading from /var/backups/slapd-2.3.35-1ubuntu0.2:
  - directory dc=blaireau...
  - directory dc=blaireau... failed.
Loading the database from the LDIF dump failed with the following
error while running slapadd:
    /etc/ldap/slapd.conf: line 108: rootdn is always granted unlimited privileges.
    /etc/ldap/slapd.conf: line 159: rootdn is always granted unlimited privileges.
    /etc/ldap/slapd.conf: line 173: unknown directive <sockbuf_max_incoming_aut> inside backend database definition.
    slapadd: bad configuration file!
dpkg: error processing slapd (--configure):
 subprocess post-installation script returned error exit status 1

This looks like a issue with the configuration, but even if the configuration is invalid slapd should not fail but instead present a debconf note or do some similar action.