tnsnames.ora and connecting client

Hi,
I have two machine, one with Oracle 8.1.... server on windows. The other with Linux and I'm trying to connect via c++ to the oracle server. I've downloaded all the library needed anf I can compile the program, but when I run it and try to connect I receive the infamous:

ORA-12154: TNS:could not resolve the connect identifier specified (if I use this connection string: username/pwd_at_tns_alias or username/pwd/@tns_alias)

While I get the other infamous:
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor (if I use this connection string: username/pwd_at_ip_address_of_the_server or username/pwd/@ip_address_of_the_server)

I've on the server all the .ora files (sqldata, tnsnames...) In the other pc (with linux and not Oracle installed) in the $ORACLE_HOME i've these dirs:
lib, network/admin, rdbms/demo, rdbms/public. Furthermore i've the same sqldata.ora and tnsnames.ora in the prevoius network/admin. I can ping the server only with the ip address... This is my tnsnames.ora:
HOLE =   (DESCRIPTION =     (ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = ip_addres)(PORT = 1521))

    )

    (CONNECT_DATA =
(SERVICE_NAME = HOLE)
    )

  )

INST1_HTTP =   (DESCRIPTION =     (ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = ip_addres)(PORT = 1521))

    )

    (CONNECT_DATA =
(SERVER = SHARED)

(SERVICE_NAME = HOLE)

(PRESENTATION = ********)
    )

  )

EXTPROC_CONNECTION_DATA =   (DESCRIPTION =     (ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
    )

    (CONNECT_DATA =
(SID = PLSExtProc)

(PRESENTATION = RO)
    )

  ) Received on Tue Dec 20 2005 - 07:34:09 CST