I've spent four hours trolling google search results and have scoured my own logs and can find nothing.
Until recently I used Webrick for all my http server needs. Now I'm going live to the outside world. So I download lighttpd-1.4.13.tar.gz and perform ./configure and make install. I add /usr/local/sbin (where lighttpd lives now) and I'm done. Fastcgi is built-in so I install no other stuff.
I go to the top level of my ROR app (/home/smiller/beamon-erp) and perform: script/server
Since lighttpd is on path it runs it instead of webrick. Realizing there's no lighttpd.conf in my config directly, it copies one in from /usr/local/lib/ruby/gems/1.8/gems/rails-1.1.6/configs/lighttpd.conf and then is off and running just fine.
I start my browser (firefox on RH linux) to localhost:3000 and I immediately get this error: