Mostafa Daneshvar wrote:

I installed a new wiki in my site. During installation i got this warning "Warning: A value for session.save_path has not been set in PHP.ini. If the default value causes problems with saving session data, set it to a valid path which is read/write/execute for the user your web server is running under." After I changed preferred language wiki doesn't work and always this error appears "Call to undefined method Language::localisationexist()"

Which version? Which language? What extensions are you using? There's no call to localisationexist() on trunk. Consider updating.