Some more information from the README of DBD::Oracle 1.18a
From: John Scoles <scoles (at) pythian.com>
Date: Fri, 29 Sep 2005 10:48:47 -0700 (EST)
Subject: RE: Oracle 10g Instantclient
The Makefile.PL will now work for Oracle 10g Instantclient. To have
both the Compile and
the test.pl to work you must first have the LD_LIBRARY_PATH correctly
set to your
"instantclient" directory.
(http://www.oracle.com/technology/tech/oci/instantclient/instantclient.h
tml)
The present version of the make creates a link on your "instantclient"
directory as follows
"ln -s libclntsh.so.10.1 libclntsh.so". It is needed for both the
makefile creation and the compile
but is not need for the test.pl. It should be removed after the compile.
If the Makefile.PL or make fails try creating this link directly in your
"instantclient" directory.
Hoping this could solve the problem...