I got a Donvier Ice Cream maker at a rummage sale recently and just tried to use it tonight. I followed the instructions and had a real problem with it. I positioned the blades (dasher) in the middle of the frozen cylinder as directed, then poured the frozen yogurt mixture into it. When I tried to put the lid on but found that the blades had displaced. I couldn't get the top all the way on and therefore couldn't get the crank handle on it or get it turning. Within a minute or so I had a frozen crust around the edges and realized it would be an even bigger mess to pour out the mixture and start over. Can anyone tell me what I did wrong, or a tip on how to avoid this difficulty? I'm stirring it by hand with non-metal utensils in the meantime.