Ember app fails in ie9 - blank screen originating from active-model-serializer?

I'm having a problem getting my ember app to work in ie9. I'm using:

DEBUG: ------------------------------- 
DEBUG: Ember      : 1.13.3 
DEBUG: Ember Data : 1.13.5 
DEBUG: jQuery     : 1.11.3 
DEBUG: -------------------------------

I'm getting this error:

Error while processing route: index, Adapter operation failed

And a blank screen. I think i've tracked the issue down to the serializer. I'm currently using ActiveModelSerializer. When i remove it, I get more error messages but the errors are consistent across browsers. Any idea what could be occuring?