Please attach the files in /var/log/dist-upgrade/* to this bugreport (especiall apt-term.log).
It looks like the error is in slapd:
2009-04-25 10:13:16,078 ERROR got an error from dpkg for pkg: '/var/cache/apt/archives/slapd_2.4.15-1ubuntu3_amd64.deb': 'subprocess pre-installation script returned error exit status 1
Thanks for your bugreport.
Please attach the files in /var/log/ dist-upgrade/ * to this bugreport (especiall apt-term.log).
It looks like the error is in slapd: apt/archives/ slapd_2. 4.15-1ubuntu3_ amd64.deb' : 'subprocess pre-installation script returned error exit status 1
2009-04-25 10:13:16,078 ERROR got an error from dpkg for pkg: '/var/cache/
Thanks Michael