BUG #6305: cann't reinstall postgresql

The following bug has been logged online:

Bug reference: 6305
Logged by: nadhiya
Email address: nadhiyacse07(at)gmail(dot)com
PostgreSQL version: 8.4
Operating system: ubuntu 10.04
Description: cann't reinstall postgresql
Details:

i installed openerpV6.0.3 server and client i worked on that but suddenly i
cannot connect with the postgres,i got cannot access server.key,after that i
changed file permissions and private key.but no one is work.

now i remove and reinstall postgres

i got dpkg error always while using sudo apt - get command.

i used most of the way we mentioned in the documentation but i can't solve
this.

please help me to solve this problem i spent more than 2 days.

error:
ubuntu(at)ubuntu-laptop:~$ sudo apt-get install
[sudo] password for ubuntu:
Sorry, try again.
[sudo] password for ubuntu:
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
After this operation, 0B of additional disk space will be used.
Setting up postgresql-8.4 (8.4.9-0ubuntu0.10.04) ...
* Starting PostgreSQL 8.4 database server
* Error: could not exec /usr/lib/postgresql/8.4/bin/pg_ctl
/usr/lib/postgresql/8.4/bin/pg_ctl start -D /var/lib/postgresql/8.4/main -l
/var/log/postgresql/postgresql-8.4-main.log -s -o -c
config_file="/etc/postgresql/8.4/main/postgresql.conf" :

[fail]
invoke-rc.d: initscript postgresql-8.4, action "start" failed.
dpkg: error processing postgresql-8.4 (--configure):
subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of postgresql:
postgresql depends on postgresql-8.4; however:
Package postgresql-8.4 is not configured yet.
dpkg: error processing postgresql (--configure):
dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup
error from a previous failure.
Errors were encountered while processing:
postgresql-8.4
postgresql
E: Sub-process /usr/bin/dpkg returned an error code (1)