Sinatra setup in bluehost

.htaccess

AddHandler fcgid-script .fcgi
AddHandler cgi-script .cgi
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ dispatch.fcgi [QSA,L]

dispatch.fcgi

#!/home2/salatecs/.rvm/rubies/ruby-1.9.3-p194/bin/ruby

require 'rubygems'

fastcgi_log = File.open("fastcgi.log", "a")
STDOUT.reopen fastcgi_log
STDERR.reopen fastcgi_log
STDOUT.sync = true

print %x[which ruby]
# You must put the gems on the path
ENV["GEM_HOME"] = "/home2/salatecs/.rvm/gems/ruby-1.9.3-p194@global"
# sinatra should load now
require 'sinatra'

module Rack
  class Request
    def path_info
      @env["REDIRECT_URL"].to_s
    end
    def path_info=(s)
      @env["REDIRECT_URL"] = s.to_s
    end
  end
end

require_relative 'app'

builder = Rack::Builder.new do
  use Rack::ShowStatus
  use Rack::ShowExceptions
  
  run Sinatra::Application
end

Rack::Handler::FastCGI.run(builder)

To Install fcgi:

wget http://www.fastcgi.com/dist/old/fcgi-2.2.2.tar.gz
tar -zxvf fcgi-2.2.2.tar.gz
cd fcgi-2.2.2
mkdir $HOME/src
./configure --prefix=$HOME/src/fcgi
make && make install
gem install fcgi -r -- --with-fcgi-include=$HOME/src/fcgi/include --
with-fcgi-lib=$HOME/src/fcgi/lib

Also make sure that you are using sinatra classic, instead of modular. Modular doesn't play well with FastCGI.