We're having issues with our kitty too. All of a sudden he decided he doesn't want to use the litter anymore and will do his business on the carpet, he does wee in the toilet though so he's a pretty clever kitty. I think he may be protesting the litter so we've changed it to a new type, hopefully he gets the message.

I guess we just have to give them lots of praise when they do the right thing.

Good luck!!!