In this case I would say you are missing the .ora files in the instant client directory

By they way no one but me actully look at this list (and I only when I have some spare time)

You would be much better off posting this at http://www.nntp.perl.org/group/perl.dbi.users/ or raise a RT ticket at http://rt.cpan.org/Dist/Display.html?Queue=DBD-Oracle