Checking the help function I found:
I checked the settings of irtual server and found that these settings exactly the same as with previous installations, where I had no problems with any installation.Session not working
(start) You have session module but not working properly in your system. Perhaps this is due to some restriction of your PHP system, for example session functions are disabled or open basedir enabled. Check your installation and ask your provider for enable.
Any idea what can be wrong?