Lighttpd and rails?

Hi everyone,
I’m trying to run my rails app on a web hosting.
I’m having problem with lighttpd as it’s giving me this error
Errno::ENOENT in LoginController#finishnew
No such file or directory - chat/chat.495
This functions suppose to create a new chat.495 file.

I try running webrick, and everything goes normal, so I’m guessing it’s
some config with lighttpd

Any advice?

Thank you