looks exellent! if the possibility to show grafs and see your improvments in weights and your own weight over time I would have everything I would ever need in a gymprogram.
That was not so good. I guess it is crashing because I read from history.xml. I have changed so you now should be able to save the weight for all sets and not just one weight/exercise. Maybe it works if you delete history.xml else I have to figure it out tomorrow, time to sleep now!