August 15th, 2014, 19:04
Well that was simple.
Exceeded polygon count for a LOD. Deleted all of the rafts and it exported just fine at 13,030 polygons. The polygon count cap is about 18,000 to 19,000 in my testing for a single LOD. Have yet to hit a cap for the whole model with many LODs. I think the max I have ever done for a model including interior and all exterior LODs is 38,752 for the rebuild of the stock B-24D to a B-24J.
Your model need to go on a major diet.... Try to get under 15,000 polygons and do the polygon count with ALL parts as Editable Mesh or the count will be wrong.