You are using .vrmat files from 3dsmax to SketchUp, right?
If this is the case, I have seen a case in the past of a crash in V-Ray for SketchUp due to it not converting properly a V-Ray 3dsmax material.
This has nothing to do with Transmutr. You will get the same result if you import the .vrmat directly using V-Ray for SketchUp.
This is why I suggest you contact Chaos Group directly.