I don't think time is passing correctly on my game - and I absolutely, positively have not in any way 'altered' time on my computer.  I leave them on 'fast' mode (plenty of food now) and they are working at the 2nd hut.  ALL of them - yet when I come back, they're still at the same percentage completion I left them at.  They don't seem to DO anything when the game is 'closed' - as soon as I open the game again, they all start 'building a hut'.  
I thought there was a problem also when I was working them at the research table - they didn't make a lot of progress, it seemed.  But I kept the game open all morning and they finally got enough tech points to move up on the nature tract.  
Please advise.  I read the 'faq' sections about potential issues and it seems to imply that it's typically related to altering the clock on your computer - but I haven't, honest. 
Thanks.