Hi Shah Alam,
Thanks for your post. If I understand correctly, your client wants to be able to have users log into the site and post there own events. You might want to check out our Community Events plugin, which is designed to do that from the front end of the site. You can control the event submissions on the backend.
Another option is to use our regular calendar plugin together with some user role controls so that certain people can log into the backend of the site and create events. Would one of those options work for you?
Please note that at this time our calendar does not work with WPML. We are not able to provide support for that. My apologies for any convenience there. We hope to improve compatibility in the future.
Best,
Leah