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

hi
when i try to connect to oracle thru asp.net i get this error..
ORA-12154: TNS:could not resolve the connect identifier specified

i can connect to oracle from sql plus etc(toad..) but thru asp.net i get this error..how can i resolve this?

thanks a lot
Dim FConnection As New OracleConnection(strConn)
Dim FCommand As New OracleCommand("select serial from v6", FConnection)
Dim da As New OracleDataAdapter(FCommand)
Try
FConnection.Open()
da.Fill(dt)
FConnection.Close()
FCommand.Dispose()
FConnection.Dispose()
Catch typeEx As TypeInitializationException
debug.write(typeEx.Message)
Catch ex As Exception
Debug.Write(ex.Message)
Throw ex
Finally

------------
config file
<add key="OraConn" value="Data Source=ORAR;User Id=teststart;Password=teststart"/
---------------
tnsname.ora file
ORAR (DESCRIPTION (ADDRESS_LIST (ADDRESS = (PROTOCOL = TCP)(HOST = ORAR)(PORT = 1521))
)
(CONNECT_DATA (SID = ORAR)
)
)
-------------