Plone-site fails to install a plone instance in Zope

[mysticmatrix]

Binary package hint: plone-site

The plone-site is a metapackge promising to install zope as well as a plone instance of Zope under /var/lib/zope2.9/instances/plone-site.
However, installer fails to install any such instance, rendering Zope install useless.

The installer gives an error in console at the end:

           dzhandle make-instance: service user must be specified as user:group

Further , the command to start Zope gives message:

~$ sudo /etc/init.d/zope2.9 start
 * Zope2.9: no instances found.

Clearly, this indicates no plone instance was created.
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Ubuntu System used: Hardy Heron 8.04

plone-site:
  Installed: 2.5.2-3
  Candidate: 2.5.2-3
  Version table:
 *** 2.5.2-3 0
        500 http://mirror.anl.gov hardy/universe Packages
        100 /var/lib/dpkg/status

What excepted to happen: A pre created instance of plone so user gets a quick start.
What happened instead : Installer exited with an error