I am receiving the above error when performing a tnsping or sqlplus connect to a Database I have created on Oracle 817 on Windows 2000.

Despite all efforts to amend the TNSNAMES file and SQLNET.ORA file LISTENER.ORA file I still receive this error. I have created database with a global name of LITTLE, SID = LITTLE.
Services running on WIndows are:-
Oracleora8iTNSListener
OracleServiceLITTLE
Oracleora8iAgent
OracleWebAssistant


LSNRCTL status shows the following:
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for 32-bit Windows: Version 8.1.7.0.0 - Pr
tion
Start Date 20-DEC-2002 09:27:42
Uptime 0 days 2 hr. 52 min. 40 sec
Trace Level off
Security OFF
SNMP OFF
Listener Parameter File c:\ora8i\network\admin\listener.ora
Listener Log File c:\ora8i\network\log\listener.log
Services Summary...
LITTLE has 1 service handler(s)
LITTLE has 1 service handler(s)
PLSExtProc has 1 service handler(s)
dsd01 has 1 service handler(s)
dsdora81 has 1 service handler(s)

Here are my configuration Files

TNSNAMES.ORA
***************

# TNSNAMES.ORA Network Configuration File: C:\oracle\ora81\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.

ORA817 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = dsd)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = ora817)
)
)

LITTLE =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = dsd)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = LITTLE)
)
)

EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
)
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
)


SQLNET.ORA
******************
# SQLNET.ORA Network Configuration File: c:\ora8i\network\admin\sqlnet.ora
# Generated by Oracle configuration tools.

#DISABLE_OOB = ON

NAME.DEFAULT_ZONE = world

NAMES.DEFAULT_DOMAIN = world

SQLNET.AUTHENTICATION_SERVICES= (NONE)

#AUTOMATIC_IPC = OFF
#TRACE_LEVEL_CLIENT = OFF
#names.directory_path = (TNSNAMES)

NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES)

LISTENER.ORA
***********

# LISTENER.ORA Network Configuration File: c:\ora8i\network\admin\listener.ora
# Generated by Oracle configuration tools.
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = dsd)(PORT = 1521))
)
)
)

SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = c:\ora8i)
(PROGRAM = extproc)
)
(SID_DESC =
(GLOBAL_DBNAME = dsdora81)
(ORACLE_HOME = c:\ora8i)
(SID_NAME = dsdora81)
)
(SID_DESC =
(GLOBAL_DBNAME = dsd01)
(ORACLE_HOME = c:\ora8i)
(SID_NAME = dsd01)
)
(SID_DESC =
(GLOBAL_DBNAME = LITTLE)
(ORACLE_HOME = c:\ora8i)
(SID_NAME = LITTLE)
)
)