Vray 3.4 glass appear black

Hi,
one of my students is using vray 3.4 with sketchup 17- every material is good except the glass or the other translucent materials (like water) :
they all appear black!

any suggestions?

Was a similar problem posted in the public forums

here was Konstantins response:

I have attached his material aswell
Simple_Glass_Tinted_01.zip (106 KB)