You have a table somewhere in data.raw which expects a string (or possibly some other type mismatch). The game then fails to load prototypes due to that. Where is the question, and the error is not helpful. Usually the game tells the prototype in which the error occured, but sometimes stuff like ...

I have been slowly chipping away at porting a mod I forked a while ago. Slowly chipping things away during the porting to 2.0. However, after a point, I suddenly got this error message:


1.141 Error ModManager.cpp:1767: Failed to load mod "Kyus_Realistic_Electric_Trains_fix": bad argument #6 of 8 ...