Error loading mod: Error while loading technology prototype "aop-arc-furnace" (technology): Value must be a string in property tree at ROOT.technology.aop-arc-furnace.prerequisites[4]
Modifications: Age of Production

What other mods are you using? You cant just pretend i know -w-

The only mods that affect the arc furnace tech are aai industry and corrundum. Are you using either?

I'm about 95% certain the bug is caused by this change on line 46 in aai.lua:
https://github.com/AndreusAxolotl/Age-of-Production/commit/3457465f8734c0e053bc9b3a9ca8df6b1ecfe543#diff-d1f78d1c396c84e97aa62b63c371fc10246ed66668132ff2faf5a49d0b6d15bdR46

It causes the requisites of aup-arc-furnace to contain a sub-array of strings while it is supposed to be only strings

  name = "aop-arc-furnace",
  prerequisites = {
    "metallurgic-science-pack",
    "production-science-pack",
    "electrochemical-science-pack",
    "industrial-furnace",
    {
      "electrochemical-science-pack",
      "industrial-furnace"
    }
  },

I tried fixing it locally by adding each of the tech separately instead of as a table but it told me both were added twice. A proper fix (besides not adding tables) would probably be to add a check for duplicates in add_tech_prerequisites() function

Today I won't be home but i can try to put up a fix on an old computer that is where im going to be today. Won't be able to test though so if it still doesnt work let me know

Edit: Actually ignore that, i hope you dont mind waiting for tomorrow for a fix. Sorry for having you wait

If you dare to merge then this fixed it on my machine: https://github.com/AndreusAxolotl/Age-of-Production/pull/35

Thanks, ill do that. Still tomorrow though
I wouldn't be able to publish the version due to how i do it. Thanks for the help and sorry for having you wait a whole day

Hey. Yes, I have Aai Industry and Corrundum.
Hope you can sort it out.

Thanks guys

Fixed in next patch