I've been trying out vray for sketchup, using Sketchup Pro 7.1 on both my mac and pc machines, but I've been dealing with a couple issues, so if anyone could spare some wisdom, that would be much appreciated.

Issue #1:
I want to use displacement. In the material editor, when I enable displacement and hit the preview button, the preview window goes all black, as in the checkered stage and the material ball disappears. Nothing renders. This can't be a platform or a file-size issue, as I've had the same problem on six different machines, and even in blank files.

Issue #2:
Vray causes sketchup to crash. I'm running various dual-core machines, each with at least 2.33 GHz and 4GB RAM. Opening up the material editor or starting a render frequently crashes sketchup, and this has gotten so bad that I cannot even use the vray plugin on my Mac anymore.

Any ideas?