Welcome to the forum.
Have you tried deleting stuff that's in the kitchen and rebuilding it? Also try and have your Sim do the same action and see if they also do the "I can't do that" stomp.
Thanks for the great advice!! I was getting desperate! The Reaper kept showing up, and my Sims were dropping like flies! (Fortunately, I hadn't saved that part of the story)
So I deleted everything in the kitchen and re decorated. But the problem was with the refrigerator and the stove. I had to move the refrigerator into my dorm room, and move the stove to the opposite wall. Now my Sim spends much of her free time cooking and feeding her dormies.
Too bad they couldn't have seen their alternate future...my popularity would have grown!
Oh well...