I had trouble filling the circles too (I am trying this with version 15).
If you click in the space between but too close to the inner circle you will get the message "region not found".
Even when it does work it will fill the entire outer circle - I think Archicad has always done this.
So then you have to select your fill and then magic wand the inner circle to cut the hole.
For the copy multiply just use the multipy tool in the pet palette and set it to "rotate" instead of "drag".
You can also use the "Special Distribute" tool in the Edit menu but I found you can't make the elements you are distributing start at a node on the circle - you have to click on the edge (mercedes cursor).
Then you have to select and rotate their position.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11