I want to make an arm (upper- and lowerarm). If the upperarm moves, the lower
arm must move with it. If the lower arm rotates, the turning point must be on
the point it is atached to the upperarm. Just like a real person only then in
Flash, so the different bodyparts must be connected in some way. How can I
achieve this?

Can you help me please?

hello
you have to draw what animation you want. its called frame animation. so you have to draw each frame. as for cartoon animation goes this way.
thanks