darn it,
I too have been trying to find a work around to an artifact bug I have in the GenArts Sapphire plugins for Shake.
In my case I am using the S_Distort Node and get pink/purple artifacts for my efforts.
I am left with the only option to try remove the purple after the fact.
here is my purple.png for good measure
Phill
https://synapticlight.com
MacBookPro 2.5GHz, 4 GB RAM
Final Cut Studio 2
Shake 4.1
Photoshop CS2