School Bus and sims disappearing

I currently have a game starting on a Thursday night. When it gets to 8:00 a.m and the teens have to go to school, the school bus will appear. All the sims on the lot either freeze or disappear as does the school bus. This is annoying but I can resetsim the entire family and get them back to doing things. The real problem is that the delivery person is completely frozen on the other side of the road and I can't resetsim him (I know the sims name). He is completely frozen meaning I can't get any mail whatsoever. Also any sims using a computer will, after some time, disappear from the computer and reappear next to the computer. Any ideas?

(I have no custom content)