Thread:Project:Support desk/Installation problem, session data loss

I have installed mediaWiki, version 1.18.1 on a Windows 2008 R2 server under IIS. I am running PHP v 5.3.8 No matter what I do, I get "Your session data was lost! Check your php.ini and make sure session.save_path is set to an appropriate directory" error. The path is fine, the IUSR can read and write, it work fin with other php-applications we have installed. I have tried every possible modification in php.ini to make it work, but nothing.

Anyone have an idea?