Gerfried, that's my fault. It was made with a different version. I couldn't copy and paste it, so I made a new document that will work for you, almost identical to the previous one except for the sizes. I made some slight improvements as well.
Here are the steps to make the circle animation, which should take just a few minutes to do.
1) Make a circle, center it. I like the the border circle with fill of none.
2) Group the circle.
3) Group the group.
4) Click the top group's arrow and go to the group inside, the middle group.
Make the middle group's width half of what the group/circle width is. In this case that's
65 px. Type that same number into the left position, and type a minus in front of it.
5) Make the Transform Origin in the Metrics Inspector for the middle group X offset 100%.
6) Make the top group's left position that same positive number, (65 px) and the width
that same positive number.
7) Make both groups have Content Overflow hidden. Name the top group "Right."
7) On the middle group, keyframe Z rotation from 0 to 180 across fifty frames. Select the blue bar and make the animation timing linear.
8) Duplicate the top group. Change the duplicate top group name to "Left." Change the top group Rotation angle of Y to 180. Change the Left position to 0 px.
9) On the middle group, turn on the record button and change the keyframe Z rotation to start at 360 and go to 180 across fifty frames. Drag the blue animation bar to start at frame number 50 (00:01.20).
10) Select the "Right" group and the "Left" group, and group them. Name that group "Circle."
That's it. Let me know what you think.
(CircleAnimationAlt.hype.zip (22.6 KB)