Error while access network services in Oracle APEX

Incase you wanna use the pdf printing functionality or email fucntionality then you need to run this package , the package exists in the installation document , kindly! go thru it once . 

DECLARE
 ACL_PATH VARCHAR2(4000);
 ACL_ID RAW(16);
BEGIN
 -- Look for the ACL currently assigned to '*' and give APEX_030200
 -- the "connect" privilege if APEX_030200 does not have the privilege yet.

SELECT ACL INTO ACL_PATH FROM DBA_NETWORK_ACLS
 WHERE HOST = '*' AND LOWER_PORT IS NULL AND UPPER_PORT IS NULL;

-- Before checking the privilege, ensure that the ACL is valid
 -- (for example, does not contain stale references to dropped users).
 -- If it does, the following exception will be raised:
 --
 -- ORA-44416: Invalid ACL: Unresolved principal 'APEX_030200'
 -- ORA-06512: at "XDB.DBMS_XDBZ", line ...
 --
 SELECT SYS_OP_R2O(extractValue(P.RES, '/Resource/XMLRef')) INTO ACL_ID
 FROM XDB.XDB$ACL A, PATH_VIEW P
 WHERE extractValue(P.RES, '/Resource/XMLRef') = REF(A) AND
 EQUALS_PATH(P.RES, ACL_PATH) = 1;

DBMS_XDBZ.ValidateACL(ACL_ID);
 IF DBMS_NETWORK_ACL_ADMIN.CHECK_PRIVILEGE(ACL_PATH, 'APEX_030200',
 'connect') IS NULL THEN
 DBMS_NETWORK_ACL_ADMIN.ADD_PRIVILEGE(ACL_PATH,
 'APEX_030200', TRUE, 'connect');
 END IF;

EXCEPTION
 -- When no ACL has been assigned to '*'.
 WHEN NO_DATA_FOUND THEN
 DBMS_NETWORK_ACL_ADMIN.CREATE_ACL('power_users.xml',
 'ACL that lets power users to connect to everywhere',
 'APEX_030200', TRUE, 'connect');
 DBMS_NETWORK_ACL_ADMIN.ASSIGN_ACL('power_users.xml','*');
END;
/
COMMIT;