Nginx suddenly lose configure file

[luca_tony]

Dear ,
I install nginx stable version on CentOs 5.5.
It works smoothly in 5 months without errors.
But yesterday, I dont know why I can not access my website. 
After 10 minutes , I  found that ngnix lose configure files. So that
ngnix can listen on port 80 and can not be started again.
Do you think someone have my root password and remove nginx OR it's a
bug of nginx.
Thank you very much.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,182596,182596#msg-182596