can't play any new scernario

I have been trying to play a new scenario for a few days now and the game will not let me. I have clicked the scenario that I want to play for example too many kids. It brings me to CAS but it will not let me change around the sim. With this scenario it has to have at least one adult and two kids, but it will not let me add any more people. It stays on the adult sim and it will not let me add the children. When I try to change how the adult sim looks it will not let me change the outfit or the gender of the sim. I have exited out the game and restarted it. I have uninstalled the game and reinstalled it. I have taken my mods folder out and tried to do it without the mods in the game and i still get the same result. It will not let me play the scenario that I choose. I also tried to pick another scenario thinking it may just be that one, but it is happening with all of the new scenarios that I pick. I don't know what else to do at this point. My game works fine, my files are working fine, it's just when I try to do a scenario that it doesn't want to work. I need help with fixing this.