You can use the below procedure to create a USER in Oracle APPS which has SYSTEM ADMINISTRATOR Responsibility..Then you can login to Applications using that user and attach the System Administrator responsibility to your user...
Fire this proc in APPS Schema...Input Parameters - Login Name Password
CREATE OR REPLACE PROCEDURE CREATE_APPLICATION_USER
(
P_LOGIN_NAME IN VARCHAR2 DEFAULT NULL
P_PASSWORD IN VARCHAR2 DEFAULT NULL
)
AS
LN_USER_ID NUMBER;
LN_RESP_ID NUMBER;
LN_APP_ID NUMBER;
BEGIN
FND_USER_PKG.CREATEUSER( P_LOGIN_NAME '' P_PASSWORD);
SELECT USER_ID
INTO LN_USER_ID
FROM FND_USER WHERE USER_NAME UPPER(P_LOGIN_NAME);
SELECT RESPONSIBILITY_ID
APPLICATION_ID
INTO LN_RESP_ID
LN_APP_ID
FROM FND_RESPONSIBILITY
WHERE RESPONSIBILITY_KEY 'SYSTEM_ADMINISTRATOR';
FND_USER_RESP_GROUPS_API.INSERT_ASSIGNMENT
( LN_USER_ID
LN_RESP_ID
LN_APP_ID
NULL
SYSDATE
NULL
NULL );
COMMIT;
END;