'Crash' crash, or renders black ??

Latter may be due to scene and/or texture complexity. IMHO, Poser_11's 'garbage collection' can get 'maxed-out' if you do a lot of texture changing, especially 2k, 4k, 8k super-detailed textures. Save PZ3, close and re-start Poser usually helps. If necessary, down-size mega-textures using eg free Irfan View.

Don't know about Firefly, but I also tackle persistent 'renders-black' failures in Superfly by reducing my 'vols & buckets' from 1024 by binary stages to 64. At that point, probably faster to switch from my overloaded GPU cards to CPU-only, or send job to networked 'Box'...