Oracle 10g 11g X64 and 32bit (x86) oledb client application in a Windows Domain

Supponing to have a  Oracle  64bit installed on a server. A 32bit application (like oledb) to work needs the Oracle Client 32 bit.
In the following rows there are the configuration files:

X64 

listener.ora
# listener.ora Network Configuration File: C:\oracle\product\10.2.0\db_1\NETWORK\ADMIN\listener.ora
# Generated by Oracle configuration tools.

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (GLOBAL_DBNAME = orcl.maragna.local)
      (PROGRAM = extproc)
      (SID_NAME = ORCL)
      (ORACLE_HOME = C:\oracle\product\10.2.0\db_1)
    )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
    )
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = GMWEB.maragna.local)(PORT = 1521))
    )
  )

---

sqlnet.ora
# sqlnet.ora Network Configuration File: C:\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.

NAMES.DEFAULT_DOMAIN = MARAGNA.local
SQLNET.AUTHENTICATION_SERVICES= (NTS)
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

---

tnsnames.ora
# tnsnames.ora Network Configuration File: C:\oracle\product\10.2.0\db_1\NETWORK\ADMIN\tnsnames.ora
# Generated by Oracle configuration tools.

WEB.MARAGNA.LOCAL =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = LOCALHOST)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = ORCL.MARAGNA.LOCAL)
    )
  )

ORCL =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = GMWEB.maragna.local)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SID = ORCL)
      (SERVER = DEDICATED)
    )
  )

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

---

ORACLE CLIENT 32BIT (X86)

X86 - 32BIT

# sqlnet.ora Network Configuration File: C:\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.

NAMES.DEFAULT_DOMAIN = MARAGNA.local
SQLNET.AUTHENTICATION_SERVICES= (NTS)
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

---

# tnsnames.ora Network Configuration File: C:\app\giovanni\product\11.1.0\client_1\Network\Admin\tnsnames.ora
# Generated by Oracle configuration tools.

# Every line that begins with # is a comment line
#
# Create Oracle net service names, or aliases, for each database server
# you need to connect to.
#
# TNSNames.ora sample entry
#
# alias =
#  (DESCRIPTION =
#    (ADDRESS = (PROTOCOL = TCP)(HOST = myserver.mycompany.com)(PORT = 1521))
#    (CONNECT_DATA =
#      (SERVER = DEDICATED)
#      (SERVICE_NAME = orcl)
#    )
#  )
#
# You can modify the entry below for your own database.
# <data source alias> = Name to use in the connection string Data Source
# <hostname or IP> = name or IP of the database server machine
# <port> = database server machine port to use
# <database service name> = name of the database service on the server

WEB2 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = GMWEB.MARAGNA.LOCAL)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = ORCL)
    )
  )

WEB.MARAGNA.LOCAL =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = LOCALHOST)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = ORCL.MARAGNA.LOCAL)
    )
  )