With Facebooker2, can I use apprequests_create on backend

I'm trying to send apprequest on the backend, here is the code I'm trying to do it, but it always return 'Mogli::Client::HTTPException' error. My question is (1) can I do it on backend? (2) what kind of permission should I acquire ? (3) what is the correct way to use the apprequest_create?

Thank you and following is the code i'm trying to use:

friend = Mogli::User.find(friend_facebook_id.to_i, current_facebook_client)
friend.apprequests_create(
            Mogli::AppRequest.new(
         开发者_开发技巧                   :link=>"callback url",
                            :to => {:id => friend_facebook_id, :name => friend_facebook_name},,
                            :message=>"Try 1"))

Here is the application trace:

/Library/Ruby/Gems/1.8/gems/mogli-0.0.30/lib/mogli/client.rb:215:in `raise_error_if_necessary'
/Library/Ruby/Gems/1.8/gems/mogli-0.0.30/lib/mogli/client.rb:151:in `map_data'
/Library/Ruby/Gems/1.8/gems/mogli-0.0.30/lib/mogli/client.rb:116:in `post'
/Library/Ruby/Gems/1.8/gems/mogli-0.0.30/lib/mogli/model.rb:113:in `apprequests_create'