you can download it from the link i posted. but everything unique about it, was from 2007. a lot of things have changed on the internet over the past 10 years. also, since ubbfusion was a rip of UBB.threads v6 code, you'd technically be going backwards.
in addition, im not sure how well fbb works with the current php5x versions, since its rather dated.
anyways, the download of its most current version is on the link i posted above.