Foreign keys: referencing a REFERENCES doesn7t work?

I have the following schema:

create table PRODUCTS (

id                      char(12)        primary key
);


create table MOVIES (

id                      char(12)        references PRODUCTS,
volume_id               int2            not null default 1,
label_id                integer         references LABELS(id),
length                  int2            not null,

primary key (id, volume_id)
);

create table MOVIE_SERIES (

id                      serial          primary key,
title                   text            not null,
title_kana              text            not null
);

create table REL_MOVIES_SERIES (

prod_id                 char(12)        references MOVIES(id),
series_id               integer         references MOVIE_SERIES(id),

primary key (prod_id, series_id)
);

When trying to enter this SQL I get the following error:

ERROR:  UNIQUE constraint matching given keys for referenced table
"movies" not found


Seems that pgsql is fine when MOVIES.id references PRODUCTS.id for a
foreign key but if a table references MOVIES.prod_id for a foreign key
pgsql cannot go up the reference "tree" and follow what MOVIES.id
references to see that there really is a unique constraint ... hence I
get an error.

Am I missing something or is this a problem with pgsql?

Jc