1) That is another bug that should be fixed in next versions.
2) Frame Width/Height are the size of the particle you want to import if you have the animation speed higher than 0.
3)About the UI difference in youtube videos is due we are constantly improving the tool adding more features.
4) YOu already can do it, there are some examples like the Explosion_Orb and similar that are executed one time and after finish starts again. Look how their are done.
5) We are working on a new update that should fix most of the errors like load the thunder example and others.