WordPress.com Stats Problem

I upgraded to WordPress 2.3.3 today after fixing some other problems it caused, the only issue that lingers is an error I get when I try to enable the WordPress.com Stats plug-in.

After entering the API key, the following error message comes up:
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Warning: stats_get_blog_id(/home/content/d/e/s/desktopcadence/html/photoblog/wp-includes/class-IXR.php): failed to open stream: No such file or directory in /home/content/d/e/s/desktopcadence/html/photoblog/wp-content/plugins/stats.php on line 336

Fatal error: stats_get_blog_id(): Failed opening required ‘/home/content/d/e/s/desktopcadence/html/photoblog/wp-includes/class-IXR.php’ (include_path=’.:/usr/local/lib/php’) in /home/content/d/e/s/desktopcadence/html/photoblog/wp-content/plugins/stats.php on line 336

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I also get this after I try to post a new entry and the error disappears completely if I disable the plugin.

any idea of whats going on?