I have made another release of Arasan, to correct a few bugs:
Changes in Arasan 12.1 (Aug. 2010):
1) Remove extra "quit" output on program termination
2) Decrease thread wait time on exit
3) Fix UCI tablebase support - enable tablebases when path is set
4) Fix to outside passed pawn scoring
5) Increase king attack scores
This version also has some opening book improvements.
Downloads are at http://www.arasanchess.org.
--Jon