It's a bit of a goose chase, but you can still find the firmware required for using some Grappler cards with Mac OS X. Here's the main link to an archived version of Orange Micro's downloads. You can also go to www.archive.org and search for orangemicro.com and other long-lost favorites.
Speaking of old PCI cards, you know that when you eventually upgrade to a new Mac Pro (or a used G5), you'll have to abandon your Grappler. Like most low-end PCI cards that work in Power Mac G3s and G4s, the Grappler is a 5-volt card and won't work in modern Macs' 3.3-volt PCI slots. Such cards won't even fit in current Macs' slots, even though they look like they could - so don't try to force 'em.
