my painter crashes when i import an FBX file.

The first file loaded with an error that some parts did not have UV co-ordinates and there were also some errors on individual polygons. Reloading with Auto-unwrap checked opened OK and I was able to paint.

The second file also had UV co-ordinate errors but opened OK after checking Autounwrap and I was able to paint.

I opened the models in Blender and it looked like neither had been UV unwrapped. I also noticed a large number of ngons in the first file. I usually try and work with quads or triangles when exporting for use in other applications. Your second file had triangles (it looks like you used the triangulate modifier), but still had not been unwrapped.
You can use Painter's Autounwrap, but I prefer to manually unwrap in Blender as that way I can control where I put the seams and ensure the texel resolution is consistent between different elements.

Dave