Ember-data :TypeError: this is undefined

Here is my ember version

"DEBUG: Ember      : 1.11.0"
"DEBUG: Ember Data : 1.0.0-beta.16.1"
"DEBUG: jQuery     : 2.1.3"

and here is my main code :

App.GenerationController = Ember.Controller.extend({
    actions: {
        generation: function(){
            [...]
            var store = this.store;
            [...]
        }
    }
}

App.SsspController = Ember.Controller.extend({
    actions: {
        sssp: function(){
            [...]
            var store = this.store;
            [...]
        }
    }
}

The "generation" action is launched before "sssp". All goes smothly for the first one, but when I reach the second one, I have this error in the console : ````TypeError: this is undefined```, in ember.debug.js, line 142.

May somebody help me ? I don't have any idea where this can come from...