Oracle – sqlplus fails to start. wants *.msb files

This is my solution, hope helpful. After unzip the Oracle instant client archive I have to create some directories, move files and create tnsnames.ora manually. This is the layout after my setup:

$ pwd
/home/oracle/instantclient_11_2
$ find . -type f|egrep -v "sdk|htm|README"
./lib/ojdbc6.jar
./lib/ojdbc5.jar
./lib/xstreams.jar
./lib/libsqora.so.11.1
./lib/libnnz11.so
./lib/libociei.so
./lib/libsqlplus.so
./lib/libocijdbc11.so
./lib/libsqlplusic.so
./lib/libclntsh.so.11.1
./lib/libocci.so.11.1
./bin/adrci
./bin/sqlplus
./bin/odbc_update_ini.sh
./bin/genezi
./bin/uidrvci
./sqlplus/admin/glogin.sql
./network/admin/tnsnames.ora

Sample tnsnames.ora:

$ cat /home/oracle/instantclient_11_2/network/admin/tnsnames.ora 
ACNTUAT =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 10.54.32.10)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = acntuat)
    )
  )

Environment variables in ~/.bashrc (for all OS users)

export ORACLE_HOME=/home/oracle/instantclient_11_2
export PATH=$PATH:$ORACLE_HOME/bin
export LD_LIBRARY_PATH=$LD_LIBARY_PATH:$ORACLE_HOME/lib
export SQLPATH=$ORACLE_HOME/sqlplus/admin
export NLS_LANG=AMERICAN_AMERICA.UTF8
export NLS_DATE_FORMAT="YYYY-MM-DD HH24:MI:SS"

At this time, the command 'sqlplus user/passwd@acntuat' should work.

If python finds more than one OCI.DLL file in the path (even if they are identical) it will throw this error. (Your path statement looks like it may throw up more than one). You can manipulate the path inside your script to constrain where python will look for the supporting ORACLE files which may be your only option if you have to run several versions of oracle/clients locally.