Vray stalls during render

[kengi_ikazuchi]

I have quite a big scene and i was redering fine with basic setup:
-very low setting
-motion blur
-720x480
-Simple Two-Level
-bucket mode

Then i decided to delete about 1000 plane instances (grass alphas), and saved the file into a different name just to be safe. When i tried to render the secene again, the render stalls. 20/30-min would go by and the first bucket is still in the same spot, unrendered. I decided to return back to the original file with 1000 planes undeleted, and it rendered fine.
This happens to me on some other large scenes as well. Any ideas of this glitche, or glitch of my doing?
any help will be greatly appreciated.

[dgsantana]

i recomend you to buy the vray advanced has it has some advance features that enables you to render large scenes. we render scenes with 30 million of polys with no problems.