Problem with backgroundrb running twice?

My experience through Backgroundrb is good it’s working fine for me but
i got one issue in this pls help me out?I hope some problem in
scheduling the task?
my config


port: “3333”
timer_sleep: 60
load_rails: true
environment: development
rails_env: development
host: localhost
database_yml: config/database.yml
acl:
deny: all
allow: localhost 127.0.0.1
order: deny,allow

my worker

class PsWorker < BackgrounDRb::Rails

repeat_every 2.minutes
first_run Time.now

def do_work(args)
# This method is called in it’s own new thread when you
# call new worker. args is set to :args

logger.debug('DO_WORK '+args.inspect)

Sende1.deliver_test()

end
end

This is working fine in both windows and linux but it generate mail
twice after very two mins why?this is my problem pls give me your
suggestions.

Thanks
Varun