Sorry Isair, but when you have a model thats not all that complex and when you go and try the put a simple round on and Proe closes on you, well you get the picture. When you pay as much as you do for something like this you would think it would work most of the time. It's just not all that stable and there are ways to make a stable program. It comes down to cost and we all know companies love to cut cost. Look at PTC's maintenance. <- I'm sure I'm opening a can a worms on this one.