Somehow something didn't get built or installed. When building all of this, it'll create an Oracle.so file and place it in its proper place in your Perl lib directory. If you're getting that message, that means it didn't make it there. It may have failed to build (and somehow any indication of it disappeared with your commenting in the Makefile), you failed to execute a 'make install', it installed somewhere else, or something bizarre. Did you have to tinker with your installation after you installed DBI/DBD::Oracle?