Minecraft Version

1.18.2

Immersive Engineering Version

ImmersiveEngineering-1.16.5-5.1.0-148

Expected Behavior

I don't know

Actual Behavior

He reported an error in the background

Steps to reproduce

Start the catserver server

Debug Crash Log

https://paste.ubuntu.com/p/YySF6yYhf4/

If your version does not show up here, support for it has been ended.

you did not even include a modlist to start with helping, but from the log i would say the NPC mod "noppes.npcs" uses client side calls/objects from immerisve engineering it should not touch when running on the server, try their issue tracker first, maybe they can fix it or come up with a solution

but 1.16.5 is not supported and might get closed here soon

As @mindforger said, 1.16.5 is long out of support.