[jQuery] localScroll Problem

[Sebastián V. Würtz]

im trying to use the localScroll pluginh in many ways :)
but i receive this error when i click

               $("#comentar").click(function(){
                   $.scrollTo( '-=900', 300 );
                   return false;
               });

E.easing[this.options.easing || (E.easing.swing ? "swing" : "linear")]
is not a function
E.easing[this.options.easing || (E.easing.swing ? "swing" : "linear")]
is not a function
E.easing[this.options.easing || (E.easing.swing ? "swing" : "linear")]
is not a function
E.easing[this.options.easing || (E.easing.swing ? "swing" : "linear")]
is not a function

(latest lib for all)