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

[Oracle_user]

Hello everybody,

This is my problem:
We create in oracle 10g a database with tablespace and dbf all as TEST
In the Microsoft ODBC administrator odbcad32:

We have set this:
System DSN:
the driver: oracle 10g driver
data source name: Test_DSN
Description:test Database
Server Name:TEST
Client version: 10gR1 and later

When we test the Connection whit this:
Server Name:TEST
user:system
pass:sadmin
(sadmin is the default pass for the database TEST)
the user System is activated and has sadmin set as password.

We get this error:
'ORA-12154: TNS:could not resolve the connect identifier specified'

We checked the following:
tnsnames.ora contain this line:
Test =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.151...)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = Test)
)
)

We cannot find the problem.
NB: we can connect with success using toad, we give this information:
user :system
pass:sadmin
database:TEST

Thanks for helping us, as we are waiting now, and time is running up.

Oracle_user.