When user open link from mail: Fatal error: Class ‘NewsletterStatistics’ not found in /home/site/public_html/wp-content/plugins/newsletter/statistics/view.php on line 2
That class (NewsletterStatistics) cannot be missing… there is some other problem. Did you installed other components maybe in wp-content/extensions/newsletter?
The Update Plugin just BROKE my site.
I had to start from scratch.
Plugin uninstall all and start all over again.
Was the update this month of August 2014
Since many others updated without issue, it seems limited to your blog environment. If you ask the provider the error log file, there probably there is the reason and I can analyze it.