I have installed the Oracle 10g at the following location : -

But I was trying to ping Oracle Client from Command Prompt. See Below : -
c:\Oracle>tnsping SONIA
ERROR IS COMING no listener

MINE tnsnames.ora File : -

# tnsnames.ora Network Configuration File: C:\oracle\product\10.2.0\client_1\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.

      (ADDRESS = (PROTOCOL = TCP)(HOST = sonia)(PORT = 1521))
What this error means??? Help me in connecting to the ORACLE 10g.
I have studied on the net that for Oracle to connect three ora files need to be there. But in my ADMIN Folder two files are created by Oracle Configuration Tools names SqlNet.ORA , TNSNAMES.ORA. LISTENER.ORA file is not created.