Torquebox needs its tmpdirs to be set by applications

config.ru

#... requires

ENV['RACK_ENV'] ||= 'development'

# This tempdir stuff is important for Torquebox deployments
(tmp = '.'
dirs = [ENV['TMPDIR'], ENV['TMP'], ENV['TEMP'], '/tmp', tmp]
for dir in dirs
  unless dir.nil?
    stat = File.stat(dir)
    if stat.directory? and stat.writable? and !stat.world_writable?
      puts "**** tmpdir will be #{dir}"
      break
    end
  end
end) if %w(production staging).include?ENV['RACK_ENV']

torquebox.rb

TorqueBox.configure do
  web do |web|
    web.context '/fileserver'
  end
  ruby do
    version '1.9'
  end
  environment do
    TMPDIR '/var/torquebox'
  end
end