This is the relevant error:
Setting up vsftpd (2.0.7-0ubuntu1) ...
Adding system user `ftp' (UID 113) ...
Adding new user `ftp' (UID 113) with group `nogroup' ...
Not creating home directory `/home/ftp'.
debconf: DbDriver config: /var/cache/debconf/config.dat is locked by
another process:
*** This bug is a duplicate of bug 349469 ***
https://bugs.launchpad.net/bugs/349469
This is an apt issue, described in bug #349469. I'm marking this report
as a duplicate.
** This bug has been marked a duplicate of bug 349469
debconf: DbDriver config: /var/cache/debconf/config.dat is
** Attachment added: Dependencies.txt
http://launchpadlibrarian.net/30872075/Dependencies.txt
** Attachment added: DpkgTerminalLog.gz
http://launchpadlibrarian.net/30872076/DpkgTerminalLog.gz
--
package vsftpd 2.0.7-0ubuntu1 failed to install/upgrade: subprocess
post-installation script