TNSPing works fine. I dont know whats wrong with the listener.

tnsping orcl

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = codc182.rqinet.com)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = orcl.codc182.rqinet.com)))
OK (0 msec)
[oracle@codc182 admin]$ sqlplus scott/tiger@orcl

SQL*Plus: Release 10.2.0.1.0 - Production on Wed Nov 2 13:17:40 2005

Copyright (c) 1982, 2005, Oracle. All rights reserved.

ERROR:
ORA-12514: TNS:listener does not currently know of service requested in connect
descriptor