If the WordPress Plugin shows a count of 0 the JavaScript – Code from WordPress stats might not be loaded. I had the problem, that I created a new footer.php – file and after the stats did not work but I had valid html – code in the footer-file. (This might be the same like changing a theme and it does not work any longer) But I got it solved now. I opened the blog (normal view, not the admin panel) with the working footer file and found some code like this:
'< script src="https://stats.wordpress.com/e-XXX.js" type="text/javascript"></script>
< script type="text/javascript">
st_go({blog:'XXX',v:'ext',post:'0'});
var load_cmc = function(){linktracker_init(XXX,0,2);};
if ( typeof addLoadEvent != 'undefined' ) addLoadEvent(load_cmc);
else load_cmc();'
</script>
(The XXX are probably the individual lines) I copied out this lines and put them into the new footer-file. Now it works.
Watch out, that you are not logged in. If you are logged in, the JavaScript – Code will not be displayed, because WordPress Stats Plugin does not count you (logged in). I use the install version of WP, not a hosted version on wordpress.com. Version is 2.3.2.
Hope, that helps or gives new solution hints.