BUG #5205: Cannot ADD CONSTRAINT ... FOREIGN KEY...

The following bug has been logged online:

Bug reference: 5205
Logged by: Alain Baeckeroot
Email address: alain(dot)baeckeroot(at)laposte(dot)net
PostgreSQL version: 8.4.1
Operating system: Linux (Ubuntu 9.10)
Description: Cannot ADD CONSTRAINT ... FOREIGN KEY...
Details:

I think i could add this constraint on an existing table:
=> select id from asset except (select asset.id from asset, base where
asset.id_base = base.id);
id
----
(0 rows)

=> ALTER TABLE ONLY asset ADD CONSTRAINT asset_id_base_fkey FOREIGN KEY
(id_base) REFERENCES base(id);
ERREUR: une instruction insert ou update sur la table « asset » viole la
contrainte de clé
étrangère « asset_id_base_fkey »
DETAIL: La clé (id_base)=(196) n'est pas présente dans la table « base
».

=> select * from base where id = 196;
id | date_crea | date_modif | auth_crea |
auth_modif | ordre
-----+----------------------------+----------------------------+-----------+
------------+-------
196 | 2009-03-16 11:57:44.391607 | 2009-03-16 11:57:44.391607 | sql |
sql | 7
(1 row)

What is wrong ?
The table asset inherits from base, but it seems to be allowed and to work
(at least on the dumb test i did)