Error when calling this function....

Am I wrong to assume that I can simply call the following function 
with SELECT catalog_batch(); ?
Additionally, I am still unclear as to how I should handle the return 
type for this function.  Is what I have ok?  Should the word Complete 
in the return statement be quoted?
CREATE FUNCTION catalog_batch() RETURNS text AS '

        DECLARE
                mp3rec RECORD;
        BEGIN
                FOR mp3rec IN SELECT * FROM mp3catalog LOOP

		INSERT INTO album (title, media, path, release_date) 
VALUES (mp3catalog.album, mp3catalog.audioformat, mp3catalog.path, 
mp3catalog.year);
		INSERT INTO track (album_id, trk_no, trk_title, time, 
genre, bitrate, channel, notes) VALUES (SELECT 
currval("album_album_id_seq"), mp3catalog.track, mp3catalog.title, 
mp3catalog.time, mp3catalog.genre, mp3catalog.bitrate, 
mp3catalog.channels, mp3catalog.comment);
                INSERT INTO participant (name) VALUES (mp3catalog.artist);

		INSERT INTO performance (album_id, participant_id) 
VALUES (SELECT currval("album_album_id_seq"), SELECT 
currval("participant_participant_id_seq"));
                END LOOP;
                RETURN Complete;
        END;'

        LANGUAGE 'plpgsql';

recordings=> select catalog_batch();
NOTICE:  Error occurred while executing PL/pgSQL function catalog_batch
NOTICE:  line 9 at SQL statement
ERROR:  parser: parse error at or near "SELECT"

and from phpPgAdmin:

Database recordings

No table detected... unable to retrieve primary or unique keys for edit/delete
Error - /Library/WebServer/Documents/phpPgAdmin/sql.php -- Line: 112

PostgreSQL said: ERROR: parser: parse error at or near "SELECT"
Your query:
select catalog_batch()


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