recipe-tweaker/data-final-fixes.lua:31: bad argument #1 of 2 to 'pairs' (table expected, got nil)
stack traceback:
[C]: in function 'pairs'
recipe-tweaker/data-final-fixes.lua:31: in function <recipe-tweaker/data-final-fixes.lua:29>
(...tail calls...)
recipe-tweaker/data-final-fixes.lua:80: in main chunk
Got this error when loading "Recipe exchange string" in mod options

Something similar is happening to me.

Error loading the mod: recipe-tweaker/data-final-fixes.lua:31: bad argument #1 of 2 to 'pairs' (table expected, got nil)
stack traceback:
[C]: in function 'pairs'
recipe-tweaker/data-final-fixes.lua:31: in function <recipe-tweaker/data-final-fixes.lua:29>
(...tail calls...)
recipe-tweaker/data-final-fixes.lua:128: in main chunk
I only modified items from the base game.

This happens when the string pasted into the mod setting is invalid in some way, I've just updated the mod to have a human readable error message for it.

One of the major problems with the mod as it is now is if something happens that would cause a startup error, there's nothing you can do to fix it because you can't load into the game to edit the tweaks - I'm not sure if there's even a solution for that besides saving your tweak strings in a text file or something, that way if you make new changes and something goes wrong, you can still at least go back to something that worked.

isn't there a startup option to reset mod settings instead of simply disabling them, or am I hallucinating that

_CodeGreen okey Well, thanks, and sorry for the confusion :(

isn't there a startup option to reset mod settings instead of simply disabling them, or am I hallucinating that

yeah there is, but that just clears it to nothing and all of the tweaks go away, and you have no way of recovering them unless you have the previous tweak string you used saved somewhere