foreign key problem

hi group,

trying to create foreign key:

ALTER TABLE porder1 ADD CONSTRAINT order_exist
FOREIGN KEY (docuuserid) REFERENCES trade(tradeid) ON DELETE RESTRICT;

column docuuserid is integer in porder1
column tradeid is serial in trade and belong to primary key (single
column)

getting In EMS PostgreSQL
ERROR: insert or update on table "porder1" violates foreign key
constraint "order_exist"
DETAIL: Key (docuuserid)=(8415) is not present in table "trade".

In PostgreSQL Code Factory
SQL Error: ERROR: insert or update on table "porder1" violates foreign
key constraint "order_exist"
DETAIL: Key (docuuserid)=(8415) is not present in table "trade".

postgresql 8.4.4-1 on windows 7 ultimate 64 bit standard installation

I'm not able to figure out what should be a problem.

kindly regards

ljubomir erdeljan