Well it's a bit better but still:
<img src="http://oi41.tinypic.com/23uvbbo.jpg" border="0" />
I also have to click 2 times at the same spot sometimes to make it find a path and sometimes it still won't fine one
This is because the Astar is grid based. The problem when setting blockers is it finds the center of a cell and checks if this is inside the bounding box of the object and this is what causes overlap. I've decreased the cell size from 32 pixels to 16 for more precision. This should mean more points lie inside the blockers. Your capx I linked is updated so try again and see if its any better. Sorry for inconvenience Ize. I will possibly use a rectangle instead of a point eventually.
How did you get the object in that position in the picture? Seems odd. Need to look into the bounding box issue further. I've made an action in the Astar object "Unblock/block using position" you can use this for more control over blocking.