RenderCows are indeed a mess on the Mac platform right now. I've had it confirmed via Support that in the latest build, it just doesn't work, full-stop.

I've gone back down to the previous build - 290396 - and my DEM animation renders using the Cows (3 Macs, 2 PCs). Generally, it all grinds to a halt (not crashes) about 400 frames in, and all the Cows become stuck. I've set it going again, and it's all stopped at 167 frames. Luckily it does recover all of the rendered frames, and I'm piecing it together manually.

E-On really need to sort this out once and for all, because for those of us that use V6I for professional work are going to have to search for something else. I really do have a love / hate relationship with Vue...

sighs