[Plugin: WordPress.com Stats] Stats are only showing up for one post

me too

here I leave a screen

https://img18.imageshack.us/img18/9291/29506934.jpg

I was having the same issue when I switched to a new theme. I just Modified the title tag in the header :

was:
<title><?php friendlytitles(); ?></title>

to:

<title><?php bloginfo('name'); ?><?php wp_title(); ?></title>

and all is working again.