Referral/Affiliate Extension Translation
The English translation file is located in app/locale/en_US/TBT_RewardsReferral.csv in the latest version of the extension (update if you don't see it). You'll need to translate these files the same way the rest of MageRewards was translated and then put them in app/locale/<your_locale>/TBT_RewardsReferral.csv
You may also wish to translate the e-mails. All e-mails are stored in app/locale/en_US/template/email/rewardsref/. You can translate these files and then store the translated versions in app/locale/ <your_locale>/template/email/rewardsref/.