As anony monk has already pointed out, you should read the README file for DBD::Oracle. The README has a wealth of information on getting it to build, test and install. Since you've already got it building correctly, you should focus on the test portion of the document. You'll have to update the tests as appropriate for your database (DSN, SID, username, password, etc...) because the defaults will not work 99.9% of the time.