Hi there, i've been having an ongoing issue with TS4. Basically, relationships among sims within a household are fine and working normally but I am unable to form any new relationships outside of a household. I can meet sims outside (at venues or on the roadside etc) and they appear in my relationships panel as usual but the moment they leave they totally disappear from my relationships panel and I am unable to find them anywhere else again.
During certain career paths there is a requirement to have a certain amount of friends to get a promotion and provided I get on well with a sim when I meet them they are registering as being friends - its just that they dont seem to exist anymore. As an example, I needed to have 7 friends to get a promotion, and I achieved this by meeting sims at venues, however my relationships panel is empty - like i havent met enybody at all the whole game.
Also, I'm not sure if this is related but when moving house all the lots are vacant (I also noticed that I dont have any neighbours). In TS3 when buying a house there would be some that your couldn't buy because they were already inhabited.