It could be a simple as overlapping vertices, or Just to big for one object. Is there an error message during this crash? Or the scale of the model is so big that it went outside the bounds of the editor, To tall or just has a ridiculous scale on it from the creator. Over 65000 vertices.
Which program are you using for converting the FBX file to X file?
You can send the fbx file to my email below and I will open it to see what it going on? Send textures also if they are not embedded in the fbx file already.
I have been converting models for a while using Classic and Reloaded. Not every model will work for what ever reason. 1/2 % fail rate over 300 to 400 models.
If you have fragmotion, I would import the xfile in there, then re export it out as a different named xfile and see if that stops the crash.
Fragmotion has a way of reordering the vertices to a format that the editor will except. I use it for stubborn models that have no apparent reason to crash the editor.
Hope this helps.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit