ORA-12154: TNS:could not resolve the connect identifier specified

Hi,

I just installed Oracle Server 10.2.0.3.0 on my Windows 2003 Standard Edition SP1 VM image. I had no errors on install and was able to sqlplus system/oracle@dev1 (where dev1 was the SID i provided for the installation).

I then installed Oracle Client 10.2.0.3.0, which again completed without any errors. But now when i try to access sqlplus from a command prompt i hit the error:

C:\Documents and Settings\Administrator>sqlplus system/oracle@dev1

SQL*Plus: Release 10.2.0.3.0 - Production on Sat Feb 28 21:53:19 2009

Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.

ERROR:
ORA-12154: TNS:could not resolve the connect identifier specified


I can  connect to dev1 from OEM using system/oracle and when i go into Oracle SQL*PLUS.

The status of the database is up in OEM, with no Oracle errors, all my Oracle services (including listener) are up so the only place i can see a problem is when trying to log into the db from sqlplus at the command prompt.

There is an issue with the db as when i try to install an application which requires Oracle server and client it also fails with an error stating:

Database configuration error:

Database connection string: VERIFY
Oracle SYS Password: VERIFY

I can ping the hostname from tnsnames.ora so can anyone point me in the right direction?

tnsnames.ora file:

# tnsnames.ora Network Configuration File: D:\oracle\product\10.2.0\db_1\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.

DEV1 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = vmbase)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = dev1)
    )
  )

EXTPROC_CONNECTION_DATA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
    )
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
    )
  )


I have two sqlnet.ora files (one for client and one for server)

Client:

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

# This file is actually generated by netca. But if customers choose to
# install "Software Only", this file wont exist and without the native
# authentication, they will not be able to connect to the database on NT.

SQLNET.AUTHENTICATION_SERVICES= (NTS)

NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

Server:

# sqlnet.ora Network Configuration File: D:\oracle\product\10.2.0\db_1\network\admin\sqlnet.ora
# Generated by Oracle configuration tools.

# This file is actually generated by netca. But if customers choose to
# install "Software Only", this file wont exist and without the native
# authentication, they will not be able to connect to the database on NT.

SQLNET.AUTHENTICATION_SERVICES= (NTS)

NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)