I just upgraded to 2.0.2 yesterday and had a counterize error show up and could not even see my blog or get into the dashboard even though I deactivated all my plugins for the upgrade.
I had to delete all the files for the counterize plugin (count.php and counterize.php)and remove the code from the footer.php and header.php files then upload again and activate. I had no errors after that and it is working correctly.
I have counterize version 0.31 when I upgraded to WP 2.0.2 but I am now upgrading the counterize plugin to 0.47 since I didn’t know there was a newer version.