I'm guessing this is a mod compatibility issue, just hoping there's an easy fix... Getting
"Error in assignID, entity with name 'behemoth-biter-die' does not exist.

Source: Schall-category-5-biter (unit)."

Mod list:
"alien-biomes-hr-terrain"
"ArmouredBiters"
"bullet-trails"
"Clockwork"
"Construction_Drones"
"FluidMustFlow"
"FNEI"
"Invulnerable-Rails-and-Poles-continued"
"Krastorio2"
"Mining_Drones"
"rso-mod"
"Transport_Drones"
"VehicleSnap"
"walls-block-spitters" (There seemed to be an incompatibility with this one so I turned it off, but the issue was still there so...)

"behemoth-biter-die" is a vanilla prototype used by vanilla behemoth biter. I am really surprised it has gone missing in your game.
Guess one of your overhaul mods have removed it.

BTW, do your game still have "Behemoth Biter"?
Plus you can see from the right tooltip when hovering them. The blue line of text showing which mods have altered them. That would be useful info to help identifying the problem.

I may look into your mod list, if I have the time. But maybe doing from your side is much faster.
Assume the biter / alien / big overhaul mods have higher chances being responsible for the removal.

Hi. No reply from you. Is the problem solved?

Sorry I do not really have time to test your mod set one by one. I only tested "ArmouredBiters" and "walls-block-spitters", which seems no problems.
Anyway, I guess it is much easier to do on your side.
First try disable my mod, and read info about "Behemoth Biter", as mentioned above. That could be a big hint.
Try disable those involved mods and re-enable my mod. See if that works.
If all above cannot give the cause, then try disable all mods first. Enable my mod, then re-enable the mods one-by-one.