Problem with Yafray GI

Hi

I have a problem with the Yafray GI. How to fix these black areas on the walls?

http://img84.exs.cx/img84/2112/yaf_test.th.png

GI Method Full
Quality Low
Depht 2

Cache
ShadQu: 0.900
Prec: 8
Ref:1
Power: 3

Sunlight

I think you need to up the quality to higher or best to remove the blotchy bits.