Where is the error??in pl/sql code

Question

DECLARE
appoggio CLOB;
contenuto CLOB;
BEGIN
SELECT "CONTENT"
INTO appoggio
FROM "VER12_DOWNLOAD"
where id=V('APP_SESSION');
SELECT "FILE_PARAMS"
INTO contenuto
FROM VER03_CUSTOMERS
where(customer_id=:P32_SELETTORE_CLIENTE);
DBMS_LOB.APPEND(contenuto,appoggio);
DELETE FROM VER12_DOWNLOAD WHERE ID=V('APP_SESSION');
COMMIT;
INSERT INTO VER12_DOWNLOAD(id,content) values
(V('APP_SESSION'),contenuto);
COMMIT;
END;
ORA-22920: row containing the LOB value is not locked

Answer 1

See
http://asktom.oracle.com/pls/ask/f?p=4950:8:::::F4950_P8_DISPLAYID:1533006062995#4304882648850
Just add a FOR UPDATE to your SELECT query below to lock the row.
[P.S: You dont need a COMMIT if you are calling this in an after-submit process, the HTML DB engine automatically commits at the end of accept processing, in any case, you definitely dont need 2 commits!]
Hope this helps.