Comment 2 for bug 400785

Thank you for taking the time to report this bug and helping to make Ubuntu better.

Did you modify the slapd schemas? Did you include new schemas?

Relevant error messages:
Installing new version of config file /etc/init.d/slapd ...
  Backing up /etc/ldap/slapd.conf in /var/backups/slapd-2.4.9-0ubuntu0.8.04.2...
  Backing up /etc/ldap/slapd.conf in /var/backups/slapd-2.4.9-0ubuntu0.8.04.2... done.
failed.
Migrating slapd.conf file (/tmp/upgrade_slapd.conf.OHxVf27845) to slapd.d failed with the following error while running slaptest:
    /tmp/upgrade_slapd.conf.OHxVf27845: line 97: duplicate index definition for attr "objectClass".
    slaptest: bad configuration directory!
dpkg: error processing slapd (--configure):
 subprocess post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of slapd-dbg:
 slapd-dbg depends on slapd (= 2.4.11-0ubuntu6.1); however: