root@s2:/etc/init.d# apt-get remove --purge postgresql-8.2 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  postgresql-common postgresql-client-8.2 postgresql-client-common
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  postgresql-8.2* postgresql-plpython-8.2*
0 upgraded, 0 newly installed, 2 to remove and 0 not upgraded.
Need to get 0B of archives.
After unpacking 12.7MB disk space will be freed.
Do you want to continue [Y/n]? y
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_TIME = "de_AT.utf8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_ALL to default locale: No such file or directory
(Reading database ... 59525 files and directories currently installed.)
Removing postgresql-plpython-8.2 ...
Removing postgresql-8.2 ...
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_TIME = "de_AT.utf8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
Purging configuration files for postgresql-8.2 ...
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_TIME = "de_AT.utf8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
root@s2:/etc/init.d# rm -r /etc/postgresql /var/lib/postgresql
rm: cannot remove `/etc/postgresql': No such file or directory
root@s2:/etc/init.d# rm -r /var/lib/postgresql
rm: cannot remove `/var/lib/postgresql': No such file or directory
root@s2:/etc/init.d# apt-get install postgresql-8.2
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Suggested packages:
  oidentd ident-server
The following NEW packages will be installed:
  postgresql-8.2
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B/3372kB of archives.
After unpacking 12.4MB of additional disk space will be used.
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_TIME = "de_AT.utf8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_ALL to default locale: No such file or directory
Selecting previously deselected package postgresql-8.2.
(Reading database ... 59446 files and directories currently installed.)
Unpacking postgresql-8.2 (from .../postgresql-8.2_8.2.6-0ubuntu0.7.10.1_amd64.deb) ...
Setting up postgresql-8.2 (8.2.6-0ubuntu0.7.10.1) ...
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_TIME = "de_AT.utf8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
Error: The locale requested by the environment is invalid.
Error: could not create default cluster. Please create it manually with

  pg_createcluster 8.2 main --start

or a similar command (see 'man pg_createcluster').
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_TIME = "de_AT.utf8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_TIME = "de_AT.utf8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
root@s2:/etc/init.d# pg_createcluster 8.2 main --start
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_TIME = "de_AT.utf8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
Error: The locale requested by the environment is invalid.

There is no /etc/postgresql directory.
The script /etc/init.d/postgresql shows no effect (as it terminates due to the above mentioned error)

Martin: The script is corrupt. It will not start the database.

If you provide a working set of files, I am willing to test again.