Can you test with our CORS samples and confirm they work with Safari in your set up:
http://help.arcgis.com/en/webapi/javascript/arcgis/help/jssamples/exp_cors_buffer.html
http://help.arcgis.com/en/webapi/javascript/arcgis/help/jssamples/exp_cors_edit_points.html
I have a feeling it's a matter of getting your server configured correctly�?? support should be able to help with this. Please post back and let us know how this progresses.