The recipes for calcium plate, tungsten trioxide and tungsten trioxide smelting all use K2 items without conditions, making the mod impossible to run without K2 installed. There may be more, but at some point I stopped trying to fix all the errors and just installed K2.

I don't understand. Recipes cannot use items from other mods when they are not active. With just this mod the mentioned items do not exist and everything seems fine. Please give me a list of mods that I need in order to reproduce this.

Sorry, I should have specified I was also using SE, all of your BZ updates, all of Ashier’s updates of Planetfall’s mods (nickel, brass, etc.), and Trikop’s bismuth and manganese. Calcium plate and tungsten trioxide are used in some SE-related recipes (smart glass, organic solar cell, holmium powder…), so maybe that’s what made the difference. Also, the last error of this type that I encountered before installing K2 was something about cobalt nanotubes and/or hydroxide, so maybe also give those a look.

I had a look and it seems the main cause is the mess with K2 prefixing everything with kr-. It's a huge clusterfuck and I think I'm skipping this one. If anyone feels capable of cleaning this up, feel free to create pull requests.