I've tried the steps on post http://us.battle.net/d3/en/forum/topic/7199642111
I did steps on posts # 3 and # 5 with no solution
I notice errors in the file Users/Shared/Battle.net/Agent
One error is from May of 2012, so probably not important? However, one is from yesterday:
"Blizzard Error", cannot open.
I have mac osx 10.8