Hi Uri,
Where are you downloading the Demo Version of V-Ray from? It should just auto install to what ever version you're working on. The best way to go about doing this is to sign up on our website and download the 2.00 Demo build here: http://www.chaosgroup.com/en/2/downloads.html?s=v-ray-sketchup#demox32
If that doesn't work please email us at vraysketchup@chaosgroup.com and we can get you up and running!
Also, you should check out the V-Ray for SketchUp Forums as well: http://forums.chaosgroup.com/forum.php
Good luck getting started and let me know if you run into any more issues with the install!