pl/pgsql question

I have created a function in pl/pgsql to modify a row before it gets put 
into the database, but it seems my modification is being ignored, and 
the unmodified row is being inserted.

I have confirmed with this RAISE EXCEPTION that my "NEW" row is modified 
properly, however it is not being stored in the db.

NEW.start_date := NEW.start_date+delta;
--      RAISE EXCEPTION ''new start date: % '',NEW.start_date;
NEW.end_date := NEW.end_date+delta;

It's probably something very obvious, but I'm mystified.

Tim


--
--      Function to enforce dependencies in the table structure
--
CREATE OR REPLACE FUNCTION projtask_insert_depend () RETURNS OPAQUE AS '
DECLARE        dependent RECORD;        delta INTEGER;
BEGIN        --        --      First make sure we start on or after end_date of tasks        --      that we depend on
     --        FOR dependent IN SELECT * FROM project_depend_vw                                WHERE 
 
project_task_id=NEW.project_task_id LOOP                --                --      See if the task we are dependent on
            --      ends after we are supposed to start                --                IF dependent.end_date >
NEW.start_dateTHEN                        delta := dependent.end_date-NEW.start_date;                --      RAISE
EXCEPTION''delta: % '',delta;                        NEW.start_date := NEW.start_date+delta;                --
RAISEEXCEPTION ''new start date: % 
 
'',NEW.start_date;                        NEW.end_date := NEW.end_date+delta;                END IF;
        END LOOP;        RETURN NEW;
END;
' LANGUAGE 'plpgsql';

CREATE TRIGGER projtask_insert_depend_trig AFTER INSERT ON project_task        FOR EACH ROW EXECUTE PROCEDURE
projtask_insert_depend();