PLPGSQL errors

Hi,

I'm getting an error on a function I want to execute and I can't see why.
I've tried a few different things and tweaked my sql without joy so far.
I want to log all inserts or updates on one table to another table.

Below I have my error, function , table schema and sql insert statement.
Thanks
It's a little long and I know anyone on this list has enough work of their
own but what goes around comes around :-)

error:
[postgres(at)central postgres]$ /usr/local/pgsql/bin/psql demo -f sysinsert.sql
psql:sysinsert.sql:16: NOTICE: Error occurred while executing PL/pgSQL
function fn_sysmessages_log
psql:sysinsert.sql:16: NOTICE: at END of toplevel PL block
psql:sysinsert.sql:16: ERROR: control reaches end of trigger procedure
without RETURN

function :
CREATE function fn_sysmessages_log() RETURNS OPAQUE AS '
BEGIN
INSERT INTO sysmessages_log
(
id,
user_id,
message_date,
message_priority,
message,
status
)
VALUES
(
NEW.id,
NEW.user_id,
NEW.message_date,
NEW.message_priority,
NEW.message,
NEW.status
);
END;
' LANGUAGE 'plpgsql';

CREATE TRIGGER tr_sysmessages_log AFTER INSERT OR UPDATE ON sysmessages FOR
EACH ROW EXECUTE PROCEDURE fn_sysmessages_log();

and my 2 tables :

create table sysmessages
(
id serial PRIMARY KEY,
user_id integer NOT NULL,
message_date date DEFAULT now() NOT NULL,
message_priority char(1) CHECK( message_priority IN (1,2,3,4,5,6,7,8,9) )
NOT NULL,
message text NOT NULL,
status char(1) CHECK( status IN ('A','P','N') ) NOT NULL
);

create table sysmessages_log
(
log_id serial PRIMARY KEY,
id integer,
user_id integer NOT NULL,
message_date date DEFAULT now() NOT NULL,
message_priority char(1) CHECK( message_priority IN (1,2,3,4,5,6,7,8,9) )
NOT NULL,
message text NOT NULL,
status char(1) CHECK( status IN ('A','P','N') ) NOT NULL
);

and the insert statement which is causing the error:

INSERT INTO sysmessages
(
user_id,
message_date,
message_priority,
message,
status
)
VALUES
(
101,
'2002-10-10',
1,
'hi',
'A'
)