I'm running Deadlock Loaders and Advanced Belts but I'm getting the error on attempting to load them, "Failed to load mods: AdvancedBeltsSA/data-final-fixes.lua:136: attempt to index field 'aai-loaders-mode' (a nil value) stack traceback: AdvancedBeltsSA/data-final-fixes.lua:136: in main chunk"

I have the same problem. The list of mods includes only basic mods, Advanced Belts and Deadlock.

AdvancedBeltsSA/data-final-fixes.lua:136: attempt to index field 'aai-loaders-mode' (a nil value)
stack traceback:
AdvancedBeltsSA/data-final-fixes.lua:136: in main chunk

same bug,this mod seems must active with aai-loader mod

Sorry for the late response, took a break from Factorio for a bit.
I'll look into this

So I tested this and could not replicate the error.
Which Deadlock mod exactly are you using?
This one? https://mods.factorio.com/mod/deadlock-beltboxes-loaders
I was able to load just fine with this Advanced Belts mod.

So I tested this and could not replicate the error.
Which Deadlock mod exactly are you using?
This one? https://mods.factorio.com/mod/deadlock-beltboxes-loaders
I was able to load just fine with this Advanced Belts mod.
Yes，this deadlock loader mod，without open this mod and aai-loader ,your mod will crash at start of a game.

Again, I loaded this mod and aai-loader and deadlock mod without any issues.

Is your AAI Loader mod in 'graphics only' mode perhaps?

Advanced Belts and deadlock loader do not work without aai-loader.

同样的报错，与https://mods.factorio.com/mod/deadlock-beltboxes-loaders