Oops, looks like I completely missed your response, sorry about that.
I have no idea why it wouldn't work, one final thing you could try (if you're still having the issue) would be to go into Documents/Electronic Arts/The Sims 4/saves and removing the WonderfulWhimsMod folder.
It will be created again when you start the game up next time, but hopefully this time the settings and everything will save and work as intended.
You will lose any settings you have saved but they don't work anyway from what you're saying.