You are not connecting properly, [] is for an array reference, not an array. Try something like:

use strict;
use warnings;
use DBI;

my $dbh = DBI->connect( 'dbi:Oracle:ppp','marto','martossecretpassword
+') || die "Database connection not made: $DBI::errstr";
$dbh->disconnect();
[download]

Check out the DBD::Oracle documentation for further examples.

Martin