NAT3520 ORACLE error :1: occurred. - CALLDBPROC for Oracle

I am running the following code and getting error the error:
NAT3520 ORACLE error :1: occurred.

TEXT:
Internal ORACLE error :1: occurred.
EXPL:
ORACLE has encountered an internal error.
ACTN:
For more information see: Internal ORACLE Error Messages.

So just wondering how to resolve this? can anyone help on this.

DEFINE DATA
LOCAL
1 BUS_CUSTOMER-VIEW VIEW OF BUS_CUSTOMER
2 CUST_NAME

01 #CUST_NBR (N8) INIT <10>
01 #CUST_NAME (A100)

01 #RESPONSE (I4)
01 #RESULT (I4)

01 #NAME (A50)

END-DEFINE
*
*

CALLDBPROC ‘USR.PKG_TEST01.PR_CUST_NAME’ BUS_CUSTOMER #CUST_NBR (AD=0) #NAME (AD=A)
RESULT SETS #RESULT
/*GIVING #RESPONSE

READ RESULT SET #RESULT INTO #NAME FROM BUS_CUSTOMER
/*GIVING #RESPONSE
DISPLAY #NAME

END-RESULT

END

CREATE OR REPLACE PACKAGE BODY pkg_test01
AS

PROCEDURE pr_cust_name(p_cust_nbr IN bus_customer.cust_nbr%TYPE,
p_cust_name OUT bus_customer.cust_name%TYPE)
IS
l_cust_name bus_customer.cust_name%TYPE;
BEGIN
SELECT cust_name
INTO l_cust_name
FROM bus_customer
WHERE cust_nbr = p_cust_nbr;

p_cust_name := l_cust_name;

END pr_cust_name;

END pkg_test01;

You will need to find out what actual error code Oracle sends,
if this message really only prints :1: issue the Natural LASTMSG
command to view the message including the error code.

NAT3520 ORACLE error-24333 occurred.

.

Any thought or advise…?