Forum:My Sims won't go to work!

Okay so when my Sims get jobs, the carpool turns up, and in the little task queue, "go to work" appears, as normal. But then it cancels itself, and when I click on the workplace and command the Sim to go to work, it cancels again. My Sims are losing their jobs because of this and I have no idea how to fix it. I got the Sims 3 via Steam, so maybe it needs updated, but Steam itself is being rather funny on my PC so I'm stuck.

Just to add salt to the wound, my boyfriend has just bought me The Sims 3 Supernatural, but on disc, and I can't install it as it says I don't have The Sims 3 installed. Is there a way around this other than ordering from Steam?

Thanks!