I am getting this error trying to do a test connection on an ODBC DSN with the Oracle Instant client setup on Windows 7 32 bit. I have it working on another machine with Vista 32 bit.
Info:
1. Dir Structure is: c:\oracle\instantclient_11_2. Basic client and instant client files in the instantclient_11_2 directory, just like on the working machine.
2. c:\oracle and c:\oracle\instantclient_11_2 in system path
3. Added TNS_ADMIN to system path and pointed in to c:\oracle
4. tnsnames.ora is copied from the working machine and in c:\oracle
5. sqlnet.ora is in c:\oracle. Working copy just had "TCP.CONNECT_TIMEOUT=5" as an entry but I tried adding: NAMES.DIRECTORY_PATH= (LDAP, TNSNAMES, HOSTNAME) when it wasn't working
6. I can telnet to the oracle server and the 1521 port (defined in tnsnames.ora).
Anything else to check?
If yout tnsnames.ora
is as you said in a comment, then you're using the wrong value in your DSN. You need to use the TNS alias in the DSN, which is ABCDM
. You can't refer to the service name directly, unless you happen to have used that as the alias as well.