missing faces in yafray

Artwork Works in Progress
1

i hope someone can help.
I use to export architectural models from autocad to blender (cvs) through a 3ds file, but my last works show many errors when rendered in yafray, some sort of geometry error that cause triangles missing in rendered images (not corresponding to mesh triangles anyway). blender internal renders are working as expected. i include an example. can someone give me a good suggestion? i tried converting 3ds to obj before importing in blender and tried as well to increase the value of FACETRES variable in acad, but results are the same.
YAFRAY

http://www.hermanitosverdes.com/images/errore_1.jpg
errore_1.jpg800×600

BLENDER INTERNAL
http://www.hermanitosverdes.com/images/errore_2.jpg
errore_2.jpg800×600

2

BAd news: seems a yafray 0.0.8 bug. I used a self-compiled 0.0.8 version on linux. If i render wiyh 0.7.2 that comes with Ubuntu breezy it renders just fine and the strange problem with geometry disappears.