logilab-database #33425 ImportError: Unable to import a postgres module [rejected]

From stable debian repository debian squeeze here is what I get when trying to create a cubicweb instance

File "/usr/lib/pymodules/python2.5/logilab/common/clcommands.py", line 119, in cmd_run
  command.run(args)
File "/usr/lib/python2.5/site-packages/cubicweb/server/serverctl.py", line 326, in run
  dbcnx = _db_sys_cnx(source, 'CREATE DATABASE and / or USER', verbose=verbose)
File "/usr/lib/python2.5/site-packages/cubicweb/server/serverctl.py", line 119, in _db_sys_cnx
  cnx = system_source_cnx(source, True, special_privs=special_privs, verbose=verbose)
File "/usr/lib/python2.5/site-packages/cubicweb/server/serverctl.py", line 101, in system_source_cnx
  return source_cnx(source, system_db, special_privs=special_privs, verbose=verbose)
File "/usr/lib/python2.5/site-packages/cubicweb/server/serverctl.py", line 81, in source_cnx
  **extra)
File "/usr/lib/pymodules/python2.5/logilab/database/__init__.py", line 65, in get_connection
  module, modname = _import_driver_module(driver, drivers)
File "/usr/lib/pymodules/python2.5/logilab/database/__init__.py", line 173, in _import_driver_module
  raise ImportError('Unable to import a %s module' % driver)
ImportError: Unable to import a postgres module