What happened ???

I tryed to opdate my Word Press to version 4.0

This is the result ??

Warning: require(/hsphere/local/home/bygderad/bygderadiovest.no/wp-includes/session.php): failed to open stream: No such file or directory in /hsphere/local/home/bygderad/bygderadiovest.no/wp-settings.php on line 122 Fatal error: require(): Failed opening required ‘/hsphere/local/home/bygderad/bygderadiovest.no/wp-includes/session.php’ (include_path=’.:/hsphere/shared/apache/libexec/php5ext/php/’) in /hsphere/local/home/bygderad/bygderadiovest.no/wp-settings.php on line 122

I dont get hold of my controle panels, nothing …………..