Error opening Symphony CMS 2.3 homepage after upgrade

gistfile1.sql

Symphony Fatal Error: Could not find Event login. If it was provided by an Extension, ensure that it is installed, and enabled.

An error occurred in /home/httpd/vhosts/optident.ch/httpdocs/symphony/lib/toolkit/class.eventmanager.php around line 175

170         public static function create($handle, array $env = null){
171             $classname = self::__getClassName($handle);
172             $path = self::__getDriverPath($handle);
173
174             if(!is_file($path)){
175                 throw new Exception(
176                     __('Could not find Event %s.', array('<code>' . $handle . '</code>'))
177                     . ' ' . __('If it was provided by an Extension, ensure that it is installed, and enabled.')
178                 );
179             }
Backtrace
[/home/httpd/vhosts/optident.ch/httpdocs/symphony/lib/toolkit/class.frontendpage.php:666]
    EventManager::create();
[/home/httpd/vhosts/optident.ch/httpdocs/symphony/lib/toolkit/class.frontendpage.php:396]
    FrontendPage->processEvents();
[/home/httpd/vhosts/optident.ch/httpdocs/symphony/lib/toolkit/class.frontendpage.php:183]
    FrontendPage->__buildPage();
[/home/httpd/vhosts/optident.ch/httpdocs/symphony/lib/core/class.frontend.php:103]
    FrontendPage->generate();
[/home/httpd/vhosts/optident.ch/httpdocs/index.php:25]
    Frontend->display();
Database Query Log
[0.0003] SET character_set_connection = 'utf8', character_set_database = 'utf8', character_set_server = 'utf8';
[0.0001] SET CHARACTER SET 'utf8';
[0.0002] SELECT SQL_CACHE t1.name, t2.page, t2.delegate, t2.callback FROM `claudia_extensions` as t1 INNER JOIN `claudia_extensions_delegates` as t2 ON t1.id = t2.extension_id WHERE t1.status = 'enabled' ORDER BY t2.delegate, t1.name;
[0.0001] SELECT SQL_CACHE `session_data` FROM `claudia_sessions` WHERE `session` = '*************' LIMIT 1;
[0.0001] SELECT SQL_CACHE `id` FROM `claudia_authors` WHERE `username` = 'admin' AND `password` = '**********' LIMIT 1;
[0.0003] UPDATE claudia_authors SET `last_seen` = '2012-06-11 10:42:20' WHERE `id` = '1';
[0.0003] SELECT SQL_CACHE * FROM `claudia_authors` WHERE `id` IN (1);
[0.0002] SELECT SQL_CACHE `p`.* FROM `claudia_pages` AS `p` LEFT JOIN `claudia_pages_types` AS `pt` ON (p.id = pt.page_id) WHERE `pt`.type = 'index';
[0.0001] SELECT SQL_CACHE type FROM `claudia_pages_types` AS pt WHERE pt.page_id = 69 GROUP BY pt.type ORDER BY pt.type ASC;
[0.0002] SELECT SQL_CACHE `name` FROM `claudia_extensions` WHERE `status` = 'enabled';