2 Instances on NT server

I have 2 db instances loaded on an NT server. On the server i can connect to
both with sqlplus.
on the client i can connect to only 1 of the instances. i have 1 listener
for both instances. i copied server side tns and sql .ora's to all my client
side directories (as i have 2 oracle homes) and this doesnt work getting the
follownig error consitantly ORA- 12545 connect failed because target host or
object does not exist. changed host name in tns to ip address of host and
still get same error have done a tnsping from client and connects ok....

is this an NT thing or a SQLNET thing ?????

any assitance would by helpful.
-----------these files are in the server and client---------- # SQLNET.ORA Network Configuration File: F:\Apps\Server_Apps\oracle\ora81\network\admin\sqlnet.ora # Generated by Oracle configuration tools.

NAMES.DEFAULT_DOMAIN = cwi

SQLNET.AUTHENTICATION_SERVICES= (NTS) NAMES.DIRECTORY_PATH= (TNSNAMES, HOSTNAME) # TNSNAMES.ORA Network Configuration File: F:\Apps\Server_Apps\oracle\ora81\network\admin\tnsnames.ora # Generated by Oracle configuration tools.

DEV.CWI =
  (DESCRIPTION =
    (ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = cw_server_1)(PORT = 1521))
    )
    (CONNECT_DATA =
(SERVICE_NAME = dev.cwi)

    )
  )
TEST.CWI =
  (DESCRIPTION =
    (ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = cw_server_1)(PORT = 1521))
    )
    (CONNECT_DATA =
(SERVICE_NAME = test.cwi)

    )
  )

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

    )
  ) Received on Fri Feb 23 2001 - 10:17:32 CST