This morning I had one problem when I am trying to install postgresql-8.2 in my ubuntu box.

[email protected]:~$ sudo apt-get install postgresql-8.2
Reading package lists... Done
Building dependency tree      
Reading state information... Done
The following extra packages will be installed:
  postgresql-client-8.2 postgresql-client-common postgresql-common
Suggested packages:
  oidentd ident-server postgresql-doc-8.2
The following NEW packages will be installed:
  postgresql-8.2 postgresql-client-8.2 postgresql-client-common
  postgresql-common
0 upgraded, 4 newly installed, 0 to remove and 895 not upgraded.
Need to get 1007kB/4379kB of archives.
After unpacking 17.4MB of additional disk space will be used.
Do you want to continue [Y/n]? y
Get:1 http://au.archive.ubuntu.com gutsy/main postgresql-client-common 78 [41.9kB]
Get:2 http://au.archive.ubuntu.com gutsy-updates/main postgresql-client-8.2 8.2.6-0ubuntu0.7.10.1 [863kB]
Get:3 http://au.archive.ubuntu.com gutsy/main postgresql-common 78 [102kB]    
Fetched 1007kB in 1m49s (9209B/s)                                             
Preconfiguring packages ...
dpkg: syntax error: unknown group `root' in statoverride file
E: Sub-process /usr/bin/dpkg returned an error code (2)

Every time I try to install, always shown up something like that. Problem in statoverride file. After googling, I find one solution. Stateoverride file was locate in /var/lib/dpkg/statoverride.

[email protected]:~$ more /var/lib/dpkg/statoverride
root Debian-exim 0640 /etc/exim4/passwd.client
hplip root 755 /var/run/hplip

To remove the file use dpkg-statoverride with remove option, but dont forget to backup the file. Use this command to remove the problem :

[email protected]:~$ sudo dpkg-statoverride --remove /var/run/hplip
[email protected]:~$ sudo dpkg-statoverride --remove /etc/exim4/passwd.client
 

Then I try to install again and it work. For me it fix the problem.