When I did disable the extension by editing /etc/php5/apache2/conf.d/zarafa.ini and commenting out extension=mapi.so, I would restart the webserver/zarafa/computer and the message would not appear in /var/log/apache2/error.log. But it still would give me the same msg when trying to access webaccess or webapp page. So prob it's enabled somewhere else aswell. zarafa.ini did not change after a restart. I had to edit and manually enable it again. Then error popped up in error.log when webserver restart.