Oracle 9i and Oracle 11g

I would try copying the tnsnames.ora and sqlnet.ora from the working 11G network/admin directory to the 9i network/admin directory.  That way the alias will be consistent.

Good luck.

I tried to copy tnsnames.ora and sqlnet.ora from the working 11G network/admin directory to the 9i network/admin directory but when I try create a new ODBC with "test connection" I get this error:

Unable to Connect
SQLState=S1000
[Oracle][ODBC][Ora]:ORA-12541: TNS no listener

Have someone any idea??

You need to set Oracle_home and Oracle_sid before using them.
please use cmd --> set ORACLE_HOME='full path of other oracle home' ---> set ORACLE_SID=<new> ---> sqlplus / as sysdba

Also make sure listener is running.
use lsnrctl command. Location of listener $ORACLE_HOME/network/admin

virdi_ds,
in my case I have to set Oracle_home and Oracle_sid like this?
set ORACLE_HOME=C:\app\a.l\product\11.2.0\db_1
set ORACLE_SID=ORCL

sqlplus / as sysdba
shutdown
startup

is it right?

hi

i must agree with @ralph_rea

and Author Yes.

If by setting this parameter, you are able to connect, then next step is to change environment variables in your window machine.
To do that use the following.
Right click on My Computer, click on Advanced tab, select Environment Variables, and change ORACLE_HOME and PATH variables.
You can also change Registory, which I am not recommending right now.

I tried:
set ORACLE_HOME=C:\app\a.l\product\11.2.0\dbhome_1
set ORACLE_SID=ORCL

but when I try: sqlplus / as sysdba I get this error:
Error 14 initializing SQL*Plus
Message file sp1<lang>.msb not found
SP2-0750: You may need to set ORACLE_HOME to your Oracle software directory

If I try to start with sqlplus from: Start --> Run --> sqlplusw I get Oracle 9i version with error:
ORA-12541: TNS no listener

In Environment Variables The PATH variables is:
C:\oraclient9\bin;C:\Program Files\Oracle\jre\1.3.1\bin;C:\Program Files\Oracle\jre\1.1.8\bin;C:\app\a.l\product\11.2.0\dbhome_1\BIN;C:\app\a.l\product\11.2.0\dbhome_1\bin;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;C:\Program Files\Sybase\SQL Anywhere 9\win32;C:\Program Files\Sybase\Shared\win32;C:\Program Files\Sybase\SQL Anywhere 9\drivers;C:\Program Files\Sybase\Shared\Sybase Central 4.2;c:\Program Files\Microsoft SQL Server\90\Tools\binn\;C:\PROGRA~1\XRay

What I wrong?

C:\app\a.l\product\11.2.0\dbhome_1\BIN>set
ALLUSERSPROFILE=C:\ProgramData
APPDATA=C:\Users\a.l\AppData\Roaming
ASANY9=C:\Program Files\Sybase\SQL Anywhere 9
ASANYSH9=C:\Program Files\Sybase\Shared
CommonProgramFiles=C:\Program Files\Common Files
COMPUTERNAME=SEVER103
ComSpec=C:\Windows\system32\cmd.exe
FP_NO_HOST_CHECK=NO
HOMEDRIVE=C:
HOMEPATH=\Users\a.l
LOCALAPPDATA=C:\Users\a.l\AppData\Local
LOGONSERVER=\\DOMINIOOP
NUMBER_OF_PROCESSORS=2
OS=Windows_NT
Path=C:\oraclient9\bin;C:\Program Files\Oracle\jre\1.3.1\bin;C:\Program F
acle\jre\1.1.8\bin;C:\app\a.l\product\11.2.0\dbhome_1\BIN;C:\app\a.le
duct\11.2.0\dbhome_1\bin;C:\Windows\system32;C:\Windows;C:\Windows\System
;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files\Sybase\SQL
e 9\win32;C:\Program Files\Sybase\Shared\win32;C:\Program Files\Sybase\SQ
ere 9\drivers;C:\Program Files\Sybase\Shared\Sybase Central 4.2;c:\Progra
\Microsoft SQL Server\90\Tools\binn\;C:\PROGRA~1\XRay
PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC
PROCESSOR_ARCHITECTURE=x86
PROCESSOR_IDENTIFIER=x86 Family 15 Model 6 Stepping 2, GenuineIntel
PROCESSOR_LEVEL=15
PROCESSOR_REVISION=0602
ProgramData=C:\ProgramData
ProgramFiles=C:\Program Files
PROMPT=$P$G
PSModulePath=C:\Windows\system32\WindowsPowerShell\v1.0\Modules\
PUBLIC=C:\Users\Public
SESSIONNAME=Console
SystemDrive=C:
SystemRoot=C:\Windows
TEMP=C:\Users\A3FA9~1.LEN\AppData\Local\Temp
TMP=C:\Users\A3FA9~1.LEN\AppData\Local\Temp
TNS_ADMIN1=C:\app\a.l\product\11.2.0\dbhome_1\NETWORK\ADMIN
USERDNSDOMAIN=DOMOPENPLAN.LOCAL
USERDOMAIN=DOMOPENPLAN
USERNAME=a.l
USERPROFILE=C:\Users\a.l
WF_RESOURCES=C:\oraclient9\WF\RES\WFus.RES
windir=C:\Windows

Confusion:
You installed Oracle Apps 11i, right?
Which database are you using with it? 9i or 8i.

Apart from above, did you install Oracle Database Server 11g as well?