Verify that you are using the correct executable to spawn the workers
We populate the rails_root and pass in the type to a method that defines the watch, this is the relevant line.
ie:
w.start = "/custom/ree/bin/rake -f #{rails_root}/Rakefile resque:#{type}"
Tail your logs, I would suspect you either aren't using the right Ruby Executable, or its an unhandled dependency, and you are missing a gem.
Are you using bundler?