Errno::ENOENT after problemless start

Dear Fellow Programmers,

I have a problem, I hope you can help me:
there is a site: (actually the problem is there, you can
check it).
Few days ago we set it on production mode.
It runnin on an nginx with 3 thin clasters. Its stand up well without
any problems. Two days later suddenly an error appeared:

No such file or directory - /ror/sorsveto/
Rails.root: /ror/sorsveto/

At the moment I can restart the application if I upload a file
“restart” (without extension). Anyway if I restart the application the
error is still there.
And of course the en.yml file is there.

I don’t know why is this happens and even don’t know how to solve it.
I’ve seen some solutions about this error but mostly focused on win7
setups and single gem updates.

I hope you can tell me some usefull handling.

Előd, Czakó