The reference data included with the current version of the forge tools is actually out of date which would be causing your crashing. There are some other threads around in the modding forum that has the complete reference data for you to download sorry I don't have a link handy but im sure someone will be in to post a link at some point.
You can ofcourse make your own reference data by using any of the conversion tools that are here on the forums, DaKhronic's and Harpo's tools are great for this.
