According to what I have been told, the responsibility only gets handed to ruby after the web server can't get to or access the file in the public directory. I have already checked the permissions on /public and the underlying files and folders (755), and in my domain settings the web directory is home/username/domain_name/current/public.
Is there something else I should check? I asked dreamhost support to look at my web server configuration, and they just told me it must be my application. I do not have this problem on my dev server, or on another production server I previously deployed to, so it would be strange if the application itself was the issue. I can't do much without this, so any help would be greatly appreciated.