Error while processing route on ie8- js promises

i am using

ember: 1.8.1 ember data: 1.0.0-beta.12 ember-cli : 0.1.7

OfferRoute = Ember.Route.extend
  model: (params)->
    @store.find('offer',params.offer_id)

it works fine on Chrome but on IE8 i get "Error while processing route"

I think the issue is with the @storebecause if i use a json object instead of ```@store.find´´´work fine. Maybe something related with IE8 and js promises?