Oracle DBCA utility: "Listener is not up or database service is not registered with it"
As far as I understand, there is a database on the machine. This database should register itself on the listener. It can do so when it knows where - on which port - the listener runs. In you case the listener is on port 15321. To enable the auto registration of the instance, you should make sure that the LOCAL_LISTENER parameter is filled with the correct port number in order to be able to contact the listener.
For docu check Oracle® Database Reference 11g Release 1 (11.1)

. oraenv
[YOUR_ORACLE_SID]
sqlplus / as sysdba
-- if the instance appears not to be running:
startup
alter system set local_listener = '(ADDRESS = (PROTOCOL=TCP)(HOST=Myhost)(PORT=15321))';
-- to force immediate registration:
alter system register;


Now your database should be visible in the listener services list
listener.ora should look like this - note the PORT =

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION = 
      (ADDRESS = 
        (PROTOCOL = TCP)
        (HOST = Myhost)
        (PORT = 15321)
      )
    )
  )


check the results:

  lsnrctl services