Error inserting records using dbms_random

Hi,

We are trying to simulate a dummy load (inserting random data) into our 11.2.0.3 database but getting a syntatical error while inserting records.

Here is the setup
1)

create table customers
(
cust_id int primary key,
f_name varchar2(40),
l_name varchar2(40),
address varchar2(40),
postnr varchar2(40),
city varchar2(40),
e_mail varchar2 (40)
)
;

2)

create sequence cust_id
minvalue 0
maxvalue 99999
start with 1
increment by 1
cache 20;


3)

INSERT
INTO customers
SELECT cust_id.nextval,
dbms_random.string('U',trunc(dbms_random.value(1,40)),
dbms_random.string('U',trunc(dbms_random.value(1,40)),
dbms_random.string('U',trunc(dbms_random.value(1,40)),
dbms_random.string('U',trunc(dbms_random.value(1,40)),