Hi Abbe,
Catalyst V3 and V4 work fine on the Dual G5 computers. You should have no problems with installing the software. If you are running OS X 10.3... I would make sure it is 10.3.9. If you are running 10.4 Tiger then 10.4.6., and 10.4.7. are fine. So far 10.4.8 seems fine.