Joomla 2.5 - Language manager - Error 500

Language manager: installed languages
Installed - Site Installed - Administrator Content Overrides

When I click on "Content" I get this error:

500 - An error has occurred.
Unknown column 'a.access' in 'on clause' SQL=SELECT a.*,ag.title AS access_level,l.home AS home FROM `v8z2b_languages` AS a LEFT JOIN v8z2b_viewlevels AS ag ON ag.id = a.access LEFT JOIN `v8z2b_menu` AS l ON l.language = a.lang_code AND l.home=1 AND l.language <> '*' WHERE (a.published IN (0, 1)) ORDER BY a.title asc Unknown column 'a.access' in 'on clause' SQL=SELECT a.*,ag.title AS access_level,l.home AS home FROM `v8z2b_languages` AS a LEFT JOIN v8z2b_viewlevels AS ag ON ag.id = a.access LEFT JOIN `v8z2b_menu` AS l ON l.language = a.lang_code AND l.home=1 AND l.language <> '*' WHERE (a.published IN (0, 1)) ORDER BY a.title asc LIMIT 0, 20 Unknown column 'a.access' in 'on clause' SQL=SELECT a.*,ag.title AS access_level,l.home AS home FROM `v8z2b_languages` AS a LEFT JOIN v8z2b_viewlevels AS ag ON ag.id = a.access LEFT JOIN `v8z2b_menu` AS l ON l.language = a.lang_code AND l.home=1 AND l.language <> '*' WHERE (a.published IN (0, 1)) ORDER BY a.title asc


I've just installed it and the installation was flawless.

GO to extension manager , "Database" tab, if you see some button saying something like "click here to fix database" click on it