1. Turned board off
2. Disabled all addons
3. Started FTP (FileZilla) and started overwriting files
4. Refreshed the browser page on www.crazyengineers.com
5. Got following 'fatal error' :-
Fatal error: Class 'XenForo_Helper_Ip' not found in /path/to/library/XenForo/Session.php on line 406
File uploading is still in progress but have never encounterd any errors in all of previous upgrades that I performed. What's going on?