Вебсервер какой Apache или Nginx?
[Fri Jul 24 03:30:04 2015] [warn] child process 16465 still did not exit, sending a SIGTERM[Fri Jul 24 03:30:04 2015] [warn] child process 16466 still did not exit, sending a SIGTERM
[warn] child process 1346 still did not exit, sending a SIGTERM
example.com/module/mycheckout/backurl?reference=1324437649324197