ResolutionIn case of Webmail the error is:
A fatal error has occurred Required 'Array' not specified in DataTree SQL configuration. The file /config/conf.php should contain a $conf['storage']['params']['Array'] setting.
Mostly, Zend Optimiser or Ioncube extensions have to be upgraded to the latest versions. Run 'php -v' command to find what version you currently run.
Ioncube loader can be found at http://www.ioncube.com/loaders.php, choose the one that corresponds to your OS version.