error starting slapd during dist-upgrade

Binary package hint: update-manager

LS,

I'm reporting this bug just for the merit of reporting it; I did not look into it yet; perhaps there just is a glitch in the backend for slapd, that will be over when the upgrade is run.

Output when the error popped up:

Installing new version of config file /etc/ldap/schema/openldap.schema ...
Installing new version of config file /etc/apparmor.d/usr.sbin.slapd ...
Installing new version of config file /etc/default/slapd ...
Installing new version of config file /etc/init.d/slapd ...
  Backing up /etc/ldap/slapd.conf in /var/backups/slapd-2.4.9-0ubuntu0.8.04.3... done.
failed.

Migrating slapd.conf file (/tmp/upgrade_slapd.conf.LzdecxPEFj) to slapd.d failed with the following error while running slaptest:
    bdb(dc=lan): Program version 4.7 doesn't match environment version 0.143
    bdb_db_open: database "dc=lan" cannot be opened, err -30971. Restore from backup!
    backend_startup_one: bi_db_open failed! (-30971)
    slap_startup failed (test would succeed using the -u switch)
dpkg: error processing slapd (--configure):
 subprocess post-installation script returned error exit status 1