problem with foreign keys

Hi,
i have a problem with REFERENCES (foreign keys). i have this table:

drop table paragraph;
create table paragraph (
id int4 PRIMARY KEY,
label varchar(512),
paragraph_next int4 CONSTRAINT paragraph_fk_next REFERENCES paragraph DEFERRABLE INITIALLY DEFERRED,
paragraph_priv int4 CONSTRAINT paragraph_fk_priv REFERENCES paragraph DEFERRABLE INITIALLY DEFERRED
);

if a excute this statements a recive a CONSTRAINT probleme:

begin;
insert into paragraph values (1,'par1',null,null);
insert into paragraph values (2,'par2',null,1);
update paragraph set paragraph_next = 2 where id = 1;
end;

and then:

begin;
delete from paragraph;
insert into paragraph values (1,'par11',null,null);
insert into paragraph values (2,'par22',null,1);
update paragraph set paragraph_next = 2 where id = 1;
end;

i recive:
ERROR: paragraph_fk_next referential integrity violation - key in paragraph still referenced from paragraph

Regards,

----
Malek Shabou E-mail: Malek(dot)Shabou(at)nic(dot)fr
AFNIC France Tel: +33 1 39 63 50 15
c/o INRIA-Rocquencourt Domaine de Voluceau Fax: +33 1 39 63 55 34
B.P.105 78153 Le Chesnay Cedex