Someone

 #apt-get -t etch-backports install postgresql
Reading Package Lists... Done
Building Dependency Tree... Done
You might want to run `apt-get -f install' to correct these:
The following packages have unmet dependencies:
  locales: Depends: glibc-2.3.2.ds1-22sarge5
  postgresql-client-common: Conflicts: postgresql-client (< 7.5)
  postgresql-common: Conflicts: postgresql-client (< 7.5)
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).