Need help with : org.postgresql.util.PSQLException : ERROR: deadlock detected

hey all,

I have a stored procedure that updates a couple of tables within my
database.

org.postgresql.util.PSQLException : ERROR: deadlock detected
Detail: Process 31580 waits for AccessExclusiveLock on relation
289553 of database 285107; blocked by process 16024.
Process 16024 waits for AccessShareLock on relation 289471 of database
285107; blocked by process 31580.

All tables in that database are heavy readed, and only my stored
procedure copies some data within a table.

The process within my stored procedure is like this but I have a
couple of these within my stored procedure:

LOCK TABLE mytable IN ACCESS EXCLUSIVE MODE;

ALTER TABLE mytable DISABLE TRIGGER trg_mytable_log;

CREATE TEMPORARY TABLE mytemptable AS SELECT * FROM mytable WHERE
country_code=_country_code_to;
CREATE TEMPORARY TABLE mytemptable_log AS SELECT * FROM mytable_log
WHERE country_code=_country_code_to;
CREATE INDEX tmytemptable_idx ON mytemptable(part_num,
vehicle_names_item_id,country_code);

DELETE FROM mytable where country_code=_country_code_to;
DELETE FROM mytable_log where country_code=_country_code_to;

INSERT INTO mytable (p..............)
SELECT .
FROM mytable
WHERE ....................

INSERT INTO mytable_log (...........)
SELECT ........
FROM mytable_log
WHERE .............

INSERT INTO mytable SELECT * FROM mytemptable
WHERE ..........
INSERT INTO mytable_log SELECT * FROM mytemptable_log
WHERE .................

UPDATE mytable a SET .............................

ALTER TABLE mytable ENABLE TRIGGER trg_mytable_log;

For me it's perfectly fine to wait until the tables can get locked,
but I am actually in a loss why it happens in the first place.
I don't think that the table should have been locked at all??

Other users do only complex SELECTS on the tables...

Ries