I need help on importing objects!

[Xlr8_Mike]

Update for problem bellow:  I believe i was making the mistake of some models having the same file name.  I have since deleted a lot of models and re organized them in blender and am getting much better results! 



Hey all,

So my track is almost done! I have made multiple custom objects for it but some won't import    I can't figure out anything that i am doing differently than when the models do work.   

everything seems fine untill i try to build my tack, it then crashes right after preprocesing.

Are there any specific parameters that need to be met when modeling an object for this game?
i am mostly using the rock generator in blender.



thanks for help, here is a latest video of my track!