Need Help with Sims 3 Glitch??

On my game of sims 3 everything was working fine for about a month and then suddenly one of my sims got stuck outside unable to walk (with the sign of footprints with a red cross on it over their head) even though there was nothing infront of it. I got another sim to do the "go to ??? with sim" action, which made it move, but then another sim got stuck like that inside the house. I used the moveobject cheat which worked the first time, but then the sim got stuck waist deep into the floor :/ After about 2 months I completely erased that file, built a completely new house, but when the new sim tried to get out of bed the next 'sim' day, it walked about 3 steps and had the same problem again. I really didn't see the point in building another new house if it was just going to do the same thing, so I just quit without saving. I reloaded and tried to get another sim to go to the bathroom but again same problem. I don't really want to use the moveobjects cheat again and possibly have to restart the game again. Plese help?????