The explosionilusiondark01.nif (yes, the name is misspelled) has a severe corruption issue. The block LightRays[21] is full of invalid data: the object bounds are NaN, the rotation is NaN, and all 296 vertices have coordinates of NaN.
This guarantees crashes as well as severe lag when the mesh is used too often in one area, since the game gets overloaded trying to render multiple "infinitely large" objects.
The fix is very simple: Delete LightRays[21] and all children, remove the relevant entries from the NiControllerManager, then reorder blocks to have the correct numbers and recalculate bounds on the entire mesh.
This not only fixes the crash, it gives a noticable performance boost in situations where the mesh is used.
goes in /meshes/magic/

Attached Files:
explosionilusiondark01.nif