CRON call ends in null exception

[error] 4461#0: *186285 FastCGI sent in stderr: "PHP message
: PHP Fatal error:  Call to a member function execute() on null in /var/www/ownc
loud/cron.php on line 125" while reading response header from upstream, client:
217.13.183.252, server: cloud.mycloud.com, request: "GET /cron.php HTTP/1.1", upstre
am: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "cloud.mycloud.com", referrer: "
https://cloud.mycloud.com/"