How to buy this plugin as im not able to use it now and I cant find the page for buying it

Hello There All, its my first Topic Here And I really need Help !
I noticed That Vray Isn't rendering lights when using 64 Distributed Rendering, And If it do, it will render 4 lights as a maximum number, while it renders it normaly when 64 bit distributed is off, any solution for this problem Please ?