[Error Analysis] Sim can't return home

I have a Sim who has not graduated, but just completed his first Term in college and transportation has arrived to take him home. A screen pops up saying that he is going home and if he wants to return to university life he must reenroll but he never makes it home. When game loads back up he ends up by a fraternity house but cannot be played...Will not allow me to click his icon or see him. The game becomes unplayable at this point. I tried exiting and I clicked to save the game but when I reenter the game it is still stuck in this unplayable state. I can see around the town but cannot see any sims available to play. It also lists sims in the left household sims panel who do not belong to my household but I cannot see those characters either