Description of the issue:

after updating IE i get this msg when trying to create a new world

Crashlog:

not a crash but here is logs https://www.dropbox.com/s/yxw1a2xzxfsl58e/latest.log?dl=0

Versions & Modlist

Minecraft 1.16.5
Forge 36.0.43-45
ImmersiveEngineering-1.16.5-4.2.2-132
Frontier craft modpack

Yes.132 is broken, I get the same on a dedicated server with an existing world, so the topic needs to be chanted to .132 is unable to load. - Failed to load datapacks

Dedicated server stacktraces-
https://gist.github.com/ProsperCraft/5842c1a6ea53fa12d82a0417c0c0c829

I have the same error. And I found out that this problem occurs only when the modpack has SilentGear. If you delete it, everything works fine. (Forge 36.0.44, SilentGear-1.16.3-2.6.6+226)

with version ImmersiveEngineering-1.16.5-4.2.1-131 its able to create new world like normal

Thanks for actually providing a detailed testcase Gregorious. Figuring out which other mod was involved in this made debugging this much faster and easier.