This is a long thread and I'm sure it's been already asked, but I wasn't able to catch it. So, apologies in advance.
I've made some minor changes in the spells.2da file, but KSE wouldn't seem to agree with it. Then I've abandoned it and downloaded a mod named "Ultimate Sound Mod", causing the same problem. When I delete the spells.2da file in the Override folder, KSE starts working. Any way to make good friends with both the mod and KSE?
Thanks, and keep up the great work!