I have similer issue from last 2-3 week. I thought it is only for me because of my bad connection. [X-(]
When I update JRE 1.51 to 1.60 or later sweethome3d webpages doesnot load all the time. It needs to refresh repetedly 25 times or more. [(:|]
Later I foud that its because of clearing cookies and cache . [:>] So I excluded from clearing in my browser. Now it seems work fine.(Not sure) [:">]