So it looks like your PC needs Net Framework updated and/or whatever Frosty requires to run. List of required updates should be in the Frosty documentation I would think, I don't know.I've created a mod following a tutorial step by step and it doesn't work unfortunaly nor it applies to the game
Do a search, type 'frosty,' and click 'search titles only.' 20 threads come up, including threads on fixing mod manager issues. Answers might be in there.