Having Issue with Importing a modified Skeletal Mesh FBX file from blender (UE4-Blender-UE4)

I am currently trying to use a slightly modified UE4 editor built for Mechwarrior and I have been exporting the Skeletal Mesh files called SKMs and they are exported as FBX. When I modify the geometry and apply the new objects I can’t have any success with adding the skeleton because it gives this error. I didn’t modify the bones but I took little panels and added them to the arm of a mesh and proceeded to bind them with a already existing vertex group. Would anyone know what I would need to do in order for this to function correctly?